Yes, beta progress will be cleared upon release. That said, there are plenty of reasons to still play.
There's a founders pack up for grabs - you can earn it by reporting bugs (if you earn it, you'll receive it once the game releases). It consists of: 500 Gems, one head upload token, one body upload token, a month of VIP, and a hat exclusive to beta testers. You'll also keep your knowledge of the game, which I'm sure will come in handy upon release.