A little (judiciously applied) haptic feedback goes a long way with apps. It’s nice to have (and most users are used to having) subtle sensory cues to let us know we are interacting with the app correctly. Has nothing to do with exercises and everything to do with the basics:
– did I select the right menu?
– is this where to click?
– ooh these pleasing vibrations are making me feel safe (from a standard UX standpoint) and rewarded.

The first specific place I missed haptic feedback was when picking my birth date during signup. I was expecting a subtle ticker while flicking through the dates.