Yeah, I've tried the sliding up the wall thing before. Felt too awkward to me! haha
I'm sure if you could get to the point where you could do multiple hand stand push ups that you'd be in good shape, but if your goal is to improve your physique aesthetics, in my opinion the best way is with a good routine using weights (and dieting, of course). If I could do handstand push ups I wouldn't be doing them to build muscle.
If that's what you want to go for though, totally go for it. I'm sure if you do them you'd get better at controlling your own body weight. I just wouldn't do them solely for the purpose of building muscle or enhancing my physique.
Again, this is opinionated.
Peace