Drifting gets a lot of flak, especially from "serious" HPDE people, be that organizers or participants. Partially this is because drifting is different from grip driving, and when people share the track, everyone wants to know what everyone else is about to do. People want other drivers to be predictable. As most people don't know much about drifting, drifting cars are unpredictable to them and therefore said people do not feel safe. Then, of course, there are the issues of spinning from excessive rotation and understeer off course/into walls.
Suffice it to say that you should not be drifting at any HPDE event, at least not on purpose.
Drifting is, by far, the most effective and efficient way to learn car control, and gain huge amounts of confidence handling both understeer and oversteer.
Drifting is all about car control. You spend the entire time either inducing oversteer, maintaining oversteer or recovering from oversteer. When the oversteer does not happen as desired you have understeer (not "nothing"), so you spend the remaining time recovering from understeer.
Drifting lets you experience both oversteer and understeer for prolonged periods of time. If you go to a skid pad you might "feel" either, but especially with a wet skid pad you just don't get that much car control skills out of it. Skid pad is mostly about steady state cornering - it is pretty difficult to initiate skids when you are already at 45 degrees of steering angle. At a drift event on the other hand you will go from zero to 90 degrees of steering angle at speed, and you can bet that the result will be either massive understeer or massive oversteer.
When I watched Tokyo Drift I thought drifting was easy and grip driving was hard. Ha! The reality is exactly opposite. It will take you many attempts, probably several days of practice, to simply start a drift and drive in a circle without spinning. It will take even more days to be able to transition from right turns to left ones while drifting, then linking multiple turns together. Then try executing increasing and decreasing radius turns.
The reward of drifting is you can correct oversteer without thinking about it. One day I was driving on a highway in light rain and I came to my exit. I was driving a front wheel drive car with an "interesting" tire combination - 225/45-17 on the front and 175/70-14 in the rear. In the dry, this setup felt like it wanted to oversteer in turns or flip over - I could not tell which. On that particular off ramp, the car decided that the actual grip level was a bit lower than what I thought it was, and the rear end started swapping sides with the front end. As I was pondering why I was looking at a guardrail my hands already applied precisely the correct amount of countersteering to keep the car on the trajectory I intended for it, albeit sideways. This is what you want to happen on the track when you drop a rear tire off pavement in a turn or you hit water or fluid on the track - you want your hands to correct the car without your brain needing to think about it.
Some people catch oversteer. Usually in intermediate and even advanced groups this involves multiple tank slappers as the driver applies too much corrective input and the car oversteers the other way. A car that recovers from multiple tank slappers is typically nowhere near the limit when the first tank slapper happens. Cars that are driven close to the limit, or at all fast in rain, typically must recover in the first tank slapper. In other words, the rear end goes one way, then stops moving as the driver countersteers the car into a drift, then returns to where it belongs under control. The second tank slapper in a car being driven at the limit typically ends in either a spin or a wall impact.
The second reward of drifting is you can recognize unsalvageable oversteer way early, often right as it begins. With experience catching the slides you develop a feel for the rate of rotation that you can catch. As soon as you feel a rate exceeding that, you go both feet in and try to stop the car. Many wall impacts can be prevented by drivers going both feet in when they either don't recognize they are in a spin at all or they try to save an unsaveable situation.
I had a moment at Watkins Glen that illustrates this vividly. I was at an open track event organized by Group 52. Conditions were mildly wet. There were dry sections of the track and puddles of water elsewhere. I was doing the feel learning exercises, driving on the left and then on the right sides of the track. Finally I went back to using full track width. What this meant was that despite running on track for maybe 40 minutes straight, I was now on a line with unknown grip levels.
The first lap I did the full track width I hit a puddle in turn 1 that I previously must have driven around on either inside or outside. The car lost grip in the rear and overrotated but I recovered. I did not pay too much attention to this, probably assuming the puddle will be gone on the next lap due to me just now driving through it.
Well, the puddle did not go anywhere, but I must have taken turn 1 quite a bit faster because on the next lap I found myself in a BIG DRIFT exiting turn 1. Totally sideways. If you have never been to Watkins Glen, it has walls on both sides that are feet away from the end of pavement. I knew if I drove off perpendicular to the track direction I would have a major impact. Right there, as I was holding the drift right, I figured that if the car drifted left I would likely hit the wall, and I made the decision to go both feet in in that case to try to keep the car sliding parallel to the track rather than off it. I waited to see if the car would stabilize in the right drift or begin to rotate left. The car elected to switch directions. As soon as I felt it rotating left, I hit the brakes hard. The car came to a stop right over the middle of the exit curbing on the outside between turns 1 and 2. I checked for traffic, drove off the curb and back on track.
Later the control guy told me the corner workers were impressed with the save. My response? I knew what was going to happen before it happened.
So slap some cheap tires on the rear and learn to handle oversteer in a parking lot with nothing to hit but cones at a friendly drift event near you!