Releasing a seriously bugged project in beta is not a problem, as long as there’s a disclaimer that warns the players that it’s not the final product and bugs are expected to be ripe and abundant, there’s nothing wrong. The worst that can happen is that it won’t run at all, players will report “ehi, it doesn’t run”, and the dev will get to fix it.
The final statement is nothing more than a prejudice, and even if we assumed it to be true (and it’s not), those who are self-motivated enough to register somewhere are also self-motivated enough to give more comprehensive reports than the general public even if they don’t have to register, the act of registering does not grant them magically spring them into action nor does it spawn them out of thin air, those people exist regardless of the fact that there’s a registration process or not.
Besides, even non comprehensive reports are useful, if you got 100 players telling you “X is broken, does not work” + a screenshot, that’s already useful information right there. Not everything has to be an essay.
In the end, all this accomplishes is reducing the feedback they receive, and risk creating an echo chamber of few selected individuals that will provide feedback that might NOT be shared by the general public. Ironically, it might make the final product even worse for release.