[yaysyu]

Re your second point.

It's discoverable enough because the next thing after tapping that most people try is dragging. And any dragging across any part of the screen activates the animation for the length of the drag.

It's plenty discoverable because they've made the whole screen control the animation

[phailhaus]

"Most people" is the key word here. If discoverability hinges on hoping on what they'll try next, then that's not good. And more likely than not they're going to tap again, because why would you drag a checkbox?

If you make the animation nonlinear and pop out quickly, we don't need to hope: they'll see it immediately! It works 100% of the time, rather than only on the x% that try dragging next.