Those would be interesting literal interpretations of the idea, but I think the real purpose of most "Coffeehouse AUs" is as an excuse for the authors to write fluffier stories about characters they like in a setting more familiar to them.I'm not personally interested in the 'coffeeshop AU' thing, though I could imagine it being interesting for if:
1. It turns out running a small business is really hard. The story is like The Bear where there's a ton of stress that makes characters have breakdowns and strains their relationships with each other
2. Keep the cozy feel, but really nerd out about premodern coffee making and logistics chains. not just a handwave and be like this magitech contraption is the equivalent of a modern espresso machine. Or maybe do have magitech espresso machine, but get into more detail about who invented it, how it works, how to repair it, etc. Change the vibe up so it's not like a starbucks, but maybe like a 18th century French salon or Ottoman coffeehouse.
On that note, I am not a big fan of Modern/Nonmagical AUs, especially based on works that rely heavily on fantasy elements. I know those stories hold value to a lot of people, but I think it's often a wasted opportunity.