Personally, if it's not in a gi then it's submission wrestling to me. It doesn't bother me when others refer to it as no gi BJJ, but to me there's no such thing as 'no gi BJJ'.

BJJ is in a gi. If it's no gi then it's submission wrestling. It's all semantics really though I suppose. To each their own.

No gi is simpler, with fewer techniques to learn. Because of that I've found it easier to get better at when I've not been able to train very often. It also helps if you're the sort of person who wants to become excellent at half a dozen techniques, rather than good at hundreds of moves.