Modern smartphones perform very admirably in low light, but with some undesirable (IMO) tradeoffs: you get all kinds of weird artifacts from extrapolation, and the overall image frequently looks muddy compared to a low-light capture on a DSLR or mirrorless camera (which tend to look noisy instead). I do, however, regularly make those tradeoffs when I don't want to bug people with a flash or haul a full camera body to a show, though!
I think my use of flash indoors amounts to an aesthetic preference: I like the way skin tones come out on the combination of a ludicrous P&S flash and a "cheap" color stock like Gold 200. The tradeoff is glare and red-eye, both of which can be compensated for during compensation or with editing after the fact.