The issue with ads is generally how many and how they're vetted. It may also impact the writing of the wiki to make you read longer and therefore fit more ads. From a player perspective, I would also be concerned. I don't want a screen full of ads or be one misclick away from being hacked.
However, it's not the only wiki out there - fextralife infamously hosts a very ethically dubious wiki, but the nature of the problem is that you won't really see the ad (it's a livestream). Especially on mobile, it can be downright hidden. It's worse quality for Bg3. But, even if the main wiki becomes near unusable, we would have this and Reddit. If you have any incredibly specific questions, it can be a more helpful resource.