The news reports didn't make it clear whether the prices are set when you order or when you pay, and, of course, it's impossible to tell yet whether people will want to patronize it.
It seems like a win for food neophiles and people with odd tastes.
The advantages to the bar are novelty so it's gotten a little free publicity and smoothing out demand so that less popular items don't build up in inventory or go bad. The latter could be handled by offering specials, but this is smoother.
I don't know whether popular items will become enough more expensive than the market price to drive people away.
NonOBSF:  Brunner's Born Under Mars-- the Bears (a happy-go-lucky human culture set in contrast to the rule-oriented Centaurs) had restaurants where people rolled double or nothing for their bills. I think that would be popular, but I doubt that it would be legal in most? all? parts of the US.
 OBSF is from the glory days of rec.arts.sf.written, an unmoderated newsgroup which worked pretty well anyway. However, there was a constant temptation to write about less important things than written sf , so there came to be a custom of appending a little something about sf at the end of a post.
This is no longer obligatory in a privately owned, multi-topic lj, but my mind defaults to pulling up associations with sf, and I'm fond of the custom.
Speaking as a person with mild ADD and an associational mind, I think it would be a good thing if people added stuff from the lens through which they view the world at the end of their posts.
 SF came to mean both science fiction and fantasy. This was to disambiguate it from the commercial category "science fiction", which includes both science fiction and fantasy. As far as I can tell, the real emotional boundary line isn't between science fiction and fantasy (a lot of science fiction is just making stuff up, with a hint of scienceness for flavor, but between hard science fiction  and the range from fantasy to science fiction which has little or no accurate science.
 Hard science fiction, like almost everything else , has a disputed definition, but I think "science fiction whose story is dependent on a high proportion of science which was accepted as accurate at the time it was written" is good enough.
 Rec.arts.sf.written came up with a definition of milsf which makes sense to me: science fiction about people in a chain of command. This explains why I like the Miles books while disliking most milsf-- Miles isn't really in a chain of command.