Calling it a beta is misleading to begin with. You’re not supposed to test anything (since that’s what the previous 2 betas were for, allegedly anyway), you just get to play the expansion before others do.
It’s more appropriate to call it Early Access, since, that’s literally what it is - early access to the expansion.
Calling it a beta insinuates that it isn’t a finished product, so as to have an excuse for any bugs encountered (of which I have seen a few reported here on the forums).