One of those side benefits of the iPhone business, I suppose. “Haptic Feedback” started out, I would guess, as the vibration setting for iPhone notifications. The “vibration module” became more advanced, with support for very fine motor control, evolving into the Haptic Engine and a first-class feature when 3D Touch was announced. Not to mention its centrality to the Apple Watch and how it handles everything from notifications to scrolling the Digital Crown. It’s since spread to the MacBook line and perhaps further.