Who is stuck waiting for a toggle or checkbox to finish animating? It's not blocking anything.

The user is. You usually wait for visual confirmation before you determine that the action you performed was indeed performed.

The user isn't actually blocked from doing anything, a box is ticking, it's not a whole-screen state transition where you have to wait for things to settle before moving on. The box doesn't have to settle before you can recognize "oh, good, it accepted my input."

I like those little animations, you do not, that's fine because there is a simple solution for it:

Just respect prefers-reduced-motion when implementing animations and everyone is happy.