I feel like no matter how articulated those things are they'll always be limited because they can't show things like squishy flesh or the way a person distributes weight. Real people aren't made from solid wooden units. They're a frame of bone with muscle and skin attached in very specific ways. Those models are never going to be able to let you see things like how your shoulderblades or boobs move with your arms or how the fat gets all squished up on your abdomen when you bend forward.
I think doing figure drawing from real people or websites like this (warning: photos of nude models) is way more helpful. Do a ton of figure drawing sketches with different angles, poses, etc and eventually you'll pick up enough anatomy knowledge to do pretty much any pose from your head. That's how I learned, and when I was doing this I saw myself improving so, so much quicker than I had been before.
Edit: Oh my god I did not realize this post was one year old. Probably would not have responded if I'd noticed. But I'll keep this up because I think my advice is good and that link could be helpful