This is not something that is recommended. It is a technique that can be used in certain very rare circumstances for troubleshooting, guided by someone skilled in technical support of this software. It may also be used occasionally by advanced beta testers to simulate the fresh install conditions.
I don't expect that there is any application for such a technique for standard use of the Arduino IDE, and I also have no idea how this technique might have helped in your case (it was only intended to assist with the investigation where I described it in CPU utilization Very High - #13 by ptillisch, without any expectation that it would result in a lasting fix for the problem).
The exception is this folder:
Deleting this folder or a subset of its contents is sometimes recommended as a fix for certain problems. This path is the same for Arduino IDE 2.x as for Arduino IDE 2.x and there is some official documentation of that technique. For example:
If we do find there is some need for users to remove the other folders on their own, we can produce equivalent documentation, but I would not do it without good cause because I generally avoid recommending users to do any deletions unless absolutely necessary, since we can't assume everyone has the level of familiarity in working with file systems that is required to do this in a safe manner.