I always thought of it like this. If the main purpose of the establishment is alcohol, children shouldn’t be allowed. So bars, breweries, etc. If a restaurant also happens to have a full bar, with bar tables (different than the regular restaurant tables) then kids should be allowed in the restaurant part only.
I know no one upholds anything like that, since I see kids all over breweries and bars in restaurants but it would be nice.
Personally, I’d pay extra for a completely child free eatery though.