Nobody asked for spaced repetition nagging, and no way to turn it off. its so condescending and stupid of them. If you don't give users a choice, the only choice left to them is to stop using your app.
Yeah, maybe they could leave an option to disable this. But it takes like 30 seconds to input your pin if it's really long, and that's every few days. I for one think it's a neat solution of "now give us an 8-digit pin you've set up a year ago" problem.