Dark mode is something people desperately want, and for good reason. The main reason is that it’s easier on the eyes. Modern white interface are absolutely eye searing, especially if you’re in the dark. There’s also aesthetic preference as well as battery life concerns, as darker colors generally waste less electricity (especially with an OLED display).
Google’s apps are slowly being updated with dark modes over the last few years, though there are a few stragglers. Why Gmail doesn’t have a dark mode but Google Keep does is a mystery. However, it seems that we won’t have to wait too much longer as some users are reporting seeing a dark mode in Gmail after the latest update!
This seems to be a server side switch, so just updating won’t automatically get you the eye soothing feature. It is technically there, but it is hidden. However, some are seeing it pop up at the top of Gmail settings. This seems to be a common theme among Android 10 users, so that may be a necessity to get it.
If you don’t want to wait for that server side switch to flip, you can enable it yourself if you’re rooted. Check out this Reddit comment for the instructions, and be cautious when doing anything with root. The rest of us will impatiently wait to see the sacred setting in our favorite email app.