I'm actually in 2 minds myself over c-rap, grime, grunge, whatever. On the one hand to "sing" that stuff is very clever/needs a lot of practice (I've tried, our choir tried one year with "Hit the road Jack" and even to get the timing AND enunciation right with something like "oh baby baby baby don't you treat me so mean, you're the meanest ole woman that I've ever seen" is more than just difficult, especially whilst also keeping the rythmn.
So some of these people really are very "clever" to "sing" that stuff.
But OTOH, I just WISH they'd enunciate the words properly so that I could fully understand them. AND compared with "Hit the road jack" (for example) many of those "hits" aren't very musical are they?