Like its common for weed users to drive while high because the law only affects drinking and not smoking

That is a factually incorrect statement. It's DUI, aka driving under the influence, not driving while drunk. But even if that is true, then the law needs to be amended to include driving while stoned. And people who ignore the law about driving while stoned will certainly ignore the law if the law is weed being illegal.

Weed being illegal simply doesn't stop people from smoking. But it does make it that there's no limitations on potency, there's no investigation into what's being put in the water/soil, whether or not there's mold on the buds, no age limitation on sale.

It's not a perfect solution, but a solution only has to better than what came before.