Lots of iOS apps have the option, but ignore it and send you push ads anyway. Apple may require it to be present during app review, but they don't seem to enforce that it's used correctly.

They technically allow you to, but make it really annoying to. Uber for example:

Account > Settings > Accessibility > Communication Settings

Most apps are cross-platform. If you're already required to do it on Android, going out of your way to avoid it on iOS doesn't make a lot of sense.