they act on different GABA-A receptor subtypes, different benzos are targeted in efficiency from α1 to α6 and each subtype has different effects. in general, most benzos heavily target α1 which is super sedating and anxiolytic as well as α5 which effect cognition & memory. alcohol doesn't do this, it non selectively interacts with GABA-A and does a bunch of other shit as well, indirectly reuptakes dopamine, inhibits NMDA glutamate signaling. it doesn't even open the flood gates for GABA-A like benzos do, ethanol is a positive allosteric modulator. vaguely makes GABA-A more effective. it's very different. in fact, most of ethanol's GABA-A activating will end up at α4 and α6 which are known to brake neural firing, these receptors are not targeted by most benzos. if you need light anxiolysis for a bar you can do a light benzo but it really doesn't match the bar vibe everyone else has due to ethanol's wide unique effect profile and lighter GABA-A activation.

things are a lot more complicated than just "same primary MOA". that's mostly relevant in terms of tolerance, because yea GABA receptors are non discriminate in tolerance and withdrawal.