I mean, using sims or something as a reference; to draw (or trace) from seems okay to me in the sense that there are some very famous, very overrated comic artists in the industry that are far lazier than that. I mean, I guess it can even be useful, if you can get the pose right, to have something to draw from.
Just screenshotting and adding text though? As people have said, there's copyright issues and you wouldn't be able to profit from it (not easily anyway). Besides that, I just think it's boring. Sims doesn't have very nice graphics imo, and it couldn't really pass for comic art in most cases. Like, if you really wanna do that, at least trace over the image and recolour, make it look a little nicer.