Depends on how frequently you're interacting with this widget. The annoyance of animations comes from the integral of all time you have to spend watching them; if they're in the critical path of a workflow that you do multiple times a day they get very annoying very quickly.

I've only glanced at this app, but the goal seems to be forming a habit of doing things once a day. If you're only interacting once every 24 hours, I'd take a 1second animation with some charm over a static checkbox.