The watchOS public beta updates are still in development, which means some applications and services may not work as expected, and their data may not be backwards compatible. Apple Watch content backs up automatically to your paired iPhone. You can learn more about Apple Watch backups here. Please note Apple Watch cannot be restored to previously-released OS versions once the public beta is installed.Apple Public Beta
This year is the first Apple has released the watchOS beta to the public.
I completely understand why also with the largest reason is device recovery. Once the Apple Watch has been upgraded it is difficult to rolled back to the previous version. This would mean your watch will have to take a trip back to Apple if you hate it. Not only are you committing to having the watchOS beta but for compatibility will have to continue to use iOS beta until the final version also.
Has the watchOS 7 been working out well in beta for me? So far yes with no major issues in my experience. Is it for you? If you have any doubts then the answer is no. If you’re not okay with missing your Apple Watch for a few days while it’s being reflagged? Again I’d say no. As always the advice is don’t use on your daily driver during beta season.