No.
The deal is ones you learned to think you can then go for think faster.
There are some element on fast chess that are necesary on a complete profecional player.
Be careful with fast chess, because some bad moves maybe work on that kind of games and sometimes people believe they are good moves. In other words fast chess can reinforce bad habits.
Yes, indeed. Playing Game in 5/0, means signing up for a few extra years in Purgatory, before they let you through the Pearly Gates.
Is it good to play short games ? Does one really think or learn to think in these games ? Your thoughts ??