Recently I have received a lot of questions about blitz games. Here I will answer them all.
–> Is it useful or harmful to play blitz?
When you play a blitz game, you have no time to think. Therefore you use the things you ALREADY know. Thus you do NOT learn any new skills.
There is a huge difference between blitz and long games. In a long game you should try make THE BEST moves; while in blitz you should try NOT TO MAKE BAD MOVES. Do you realize the distinction?
Blitz develops your habit for superficial thinking. Certainly it is harmful for a long game.
In blitz you should use tactical tricks (traps). In a long game your strategic understanding matters the most.
You can see that blitz requires a different set of skills. It is like sprinting and a marathon. Is it useful to sprint