after all the purpose of a beta is to test that the game is good enough for release, therefore they are wanting to release the game as is and are hoping with the beta test some things which they couldn't find themselves are found so they can be plugged before official release.
That'd be closer to a Release Candidate really, as far as the terminology is concerned. Although the reality these days seems to be to beta-test it and simultaneously release it to the public as a release product and fix it after the damage is done.