Does anime stagnate your progress? Most people I know who draw anime never learn facial anatomy at all, nothing beyond basic figure drawing, and then just spam the same anime symbol drawings over and over again, polishing their turds.

If you try to draw realistically then you have to learn more things because the end result will always be soul crushingly bad if you don't. If you don't have a good handle on 3D forms and if you don't understand facial anatomy then no face that you draw realistically will ever look good, while it's pretty easy with anime to get to the point that you can do a decent generic anime head without knowing much else. You also can't fall into /beg/-traps like turd polishing as easily as you can if you're drawing anime.