How good is blitz chess for your overall improvment????

Generally speaking, no. Longer time controls tend to help you improve at long and shorter time controls, but the inverse is not true. I will say occasional speed chess can be useful if done the right way, but most don't use it that way - playing a ton of games fast will just condition your mind to move quickly and this is a massive weakness to your chess if you can't slow down under longer time control.

In my opinion, I find speed chess like blitz to be less harmful at higher ratings. Blitz can be good for volume of games and reinforcing patterns, but many patterns are likely unfamiliar to even average chess players, so they need the "extra thinking time."

Just my opinion as of now though; I'm not super set on it, I might alter my view slightly if presented with evidence, but as stands speed chess does not seem to help OTB rating at all - and in many cases, it can actually hurt it if the speed chess is your default.

Very interesting and insightful and I agree that having the habit of playing too fast can be very dangerous and hinder your development.Also blitz is not really about making the best moves, so if you train your mind to find playable moves all the time it could defently cause you to lose games!!

personally I use blitz to train new openings and stuff but thats just me

Blitz is useful for learning how to internalize concepts and calculate quickly, both of which would be very helpful in longer time controls. However, blitz trains you to find decent moves quickly, rather than the best moves, which is detrimental to longer time controls.

As a general rule, playing blitz will improve your tactics, but if you allow your blitz "style" to carry over into otb or rapid games, it will definitely lower your ability to play good positional moves.

It's bad . That's it

Blitz is useful for learning how to internalize concepts and calculate quickly, both of which would be very helpful in longer time controls. However, blitz trains you to find decent moves quickly, rather than the best moves, which is detrimental to longer time controls.

As a general rule, playing blitz will improve your tactics, but if you allow your blitz "style" to carry over into otb or rapid games, it will definitely lower your ability to play good positional moves.