Well, my comic starts with a NSFW segment, soooooo...
I don't see why a comic being NSFW would be a factor in anything, as long as it's interesting and the creator isn't just putting in mature content for the shock value. I'm sure some people would be deterred by it, either due to age or being more conservative, it can also depend on the content. My comic is NSFW for graphic violence and some upsetting subjects, along with a list of other things, and I can see how that would turn more people off to it than say, a comic with cussing or nudity. (Actually, why do people flag their comic for cussing? It feels like we've gotten to an age where saying damn, shit, and fuck isn't that big of a deal. But then again, I guess it depends on the environment you were raised in. Either way, it looks a bit silly.)
If you're going to make some aspects of your comic NSFW, own that shit, don't get into it halfheartedly. Also if it's bl, you'll do fine, that's like one of the most popular genres right now.