How to Reduce Transparency on Apple Watch
The Apple Watch user interface uses transparency in the Glances screens and elsewhere to add a subtle layering effect to the appearance of things on display. This is mostly an eye-candy effect, and while it’s quite subtle some users may wish to turn transparency effects off in WatchOS.
By disabling transparency on Apple Watch, it will improve the contrast of certain on screen elements, and may offer some other mild improvements to performance and battery life as well, simply because less processing power is used for drawing display elements.