It can probably help, but persoanlly I've seen improvement from just learning about proportions and stuff, and trying to incorporate that into my drawings. I still have a way to go, but at least I'm way better than just 3-4 years ago... So for me, I didn't actually have to sit down and draw a realistic drawing to improve, just learning about the basic proportions and stuff.
As for drawing realistically, it's honestly not something that interests me. I might do it just as an improvement thing, but drawing "realistic" in itself as a type of style you do just seems kind of... boring to me, personally? There's so much fun you can do with stylized and cartoony styles. Though i guess I could do it to improve if I got the time...
I admit, I kind of got burned out on trying "realistic" from art tutorials I read as a kid basically saying "look kids, if you want to ever not suck at art you have to COMPLETELY STOP DRAWING CARTOONY (also hint hint that ESPECIALLY means That Damn Manga Style) and only ONLY practise realism for years until you get decent at that, THEN you can go back to stylizing it". And I was just "well, why not both? Why not continue drawing the way you already do while also drawing realism on the side and incorporating some of those techniques?" Which I guess would be the best way to practise it, really, especially if you're not too interested in realism drawing. And well, I don't suck at drawing now, so I guess that got proven wrong.