Haven't seen the video, but I hear that cheat curls can be used to your advantage, if you use them correctly. Cheat curls shouldn't be your goto biceps exercise though. In fact, I'd only use cheat curls every once in a while to try to switch things up a bit. And by cheat curls, I mean, curls with the specific idea to cheat in mind.
I see a lot of people doing only cheat curls! Oh boy...