The last comment is not justified by the paper. The paper shows one case where the dumb thing finds tons of crashes, but several other cases in the same figure where it finds zero crashes. And the figure there is just one target program. More experiments on this issue might be interesting.

One other thing to point out: Finding crashes and finding bugs are not the same thing, as section 7 carefully argues. It could well be that many of those crashes are duplicates. The blog post I linked above also summarizes this point.