Is there any benefit in going to a bar alone?

Only if you're attractive and don't want to use dating apps for some reason.

Otherwise you're listening to shitty music while drinking overpriced watered down booze alone.

I go to bars alone all the time. I've chatted up a lot of boomers, and very seldomly a girl will get flirty. Think I've even had swinger couples get flirty with me, but nothing came of it.

mostly I have a few drinks, eat some food, and then drive home (probably just pushing up against the legal limit lol)

You get to act all mysterious and brooding sipping on your drink and pulling serious faces.

depends, are you hot? not trying to be a downer but ive hung with a crowd of girls before and it's customary to take the piss of literally anyone by themselves in a bar unless they're attractive

As if OP could afford it

Depends on the country I guess. Here I know there isn't, people go in groups so chances of talking with people and not being awkward aren't great, and they're aimed at dancing so get loud or at sports watching which it's mild fun but whatever you chat about ends when the match ends lol