The official criteria says “Restaurants can be great places to be social…” not “are”. Some will be eligible, some will not.
You have said a lot of things in your description / appeal, but did you actually provide any evidence? Links to websites that list events, show awards or other similar things go a long way to making a generic restaurant seem notable, because sadly, some people will say all sorts of nonsense to get their subs accepted.
Official criteria also state “Should not be rejected in all case”, which is the important part
After looking for while on the forum, I never saw anyone saying that you need to justify yourself with how popular your spot need to be for it to be accepted. I shouldn’t need to do a 1000 lines long article to justify myself when people get accepted for sending a tree and say “an ancient tree”…
It is often difficult to get restaurants accepted, personally I think a lot of them are eligible. I often wonder why it is more difficult to get restaurants accepted than painted utility boxes etc. (I hardly ever see people stating that they have to be great to explore)
I do think it is important to prove that it is a restaurant where you would go with your friends and family to have a proper diner, not just a place to get some (fast) food.
It also does help, if you can refer to the reviews, if it has a high review score it will help in proving it is a “great” place to socialize.
How am I supposed to know the spot need to be popular for it to be accepted when it’s not a criteria ? Especially when random things like a sign with 0 popularity get accepted without the need of a description ?
Restaurants
Restaurants can be great places to be social and great places to explore, and should not be rejected in all cases. Local restaurants and cafes in all areas often have interesting backstories, exceptional menus, or are highly rated places that someone might recommend to an out-of-town visitor.
In more rural areas, a chain restaurant may be an extremely popular local hot spot. Supporting information should make this clear in all instances, and it is helpful to provide links to newspaper articles or reviews, if available.
In addition to the clarification on restaurants, if you do any reviewing, you will have seen that “Generic Business” is a rejection reason. So if you submit a business, you must go to greater lengths to support your nomination and prove it is not “Generic.”
One or two links giving credible evidence along with a short explanation should suffice. Non-local reviewes have no idea if what you said is true, and are not expected to do the research for you.