The point of locks 'waiting' is really just that they degrade nicely under heavy contention, e.g. when more threads are trying to take the lock than you have av

The point of locks 'waiting' is really just that they degrade nicely under heavy contention, e.g. when more threads are trying to take the lock than you have available cores/harts. Busy polling will lead to terrible performance in such conditions, whereas threads that "wait" will do the right thing and leave CPU resources free for the active tasks to progress.