Even if you just want to play around with the alpha/beta, it probably wouldn't be terribly hard to come up with some issue or suggestion, or discover a bug / exploit / etc just by playing. Something everyone does, or the order that they do it, is going to be unique, so you don't necessarily have to specifically try to break any game systems, etc, to find issues. Even just giving feedback on your playstyle and character build will help Larian balance the game and adjust the difficulty levels, etc.

Of course if people have the time and inclination to put more into the alpha/beta testing, that would be great. I'm just saying that small contributions do add up, and will help make the game better and more polished.