https://www.theverge.com/2018/6/9/17444438/apple-rumor-reportedly-planning-update-apple-watch-solid-state-button-taptic-engine

Apple is reportedly planning to make a change to the Apple Watch, according to Fast Company: a future version might replace its physical button for a solid-state one that provides haptic feedback, much like the updated home button introduced in the iPhone 7 a couple of years ago.

Fast Company cites a “source with direct knowledge of Apple’s plans,” saying that the company will keep the same configuration of buttons, but that it won’t physically move, relying instead on Apple’s Taptic Engine to react to a user’s touch. The report also says that the digital crown will still physically move to scroll.