Can UltraBullet improve your level at playing chess?

@Francesco_Super no problems:)

Absolutely not.

ultrabullet won't help your game. you will get better by playing slow chess at least 5 2 +

I think it might help. But not very significantly. If you run 100 meters, would you become better at running an hour? I think, yes. However, ultrabullet differs from classical time control, probably, in another way than 100 m differs from an hour run. Also we need to ask a question, can it make your skills at classical chess even worse? It may happen, but, probably, not because of ultrabullet, but because you don't play classical for some time, which is dedicated to ultrabullet. Ultrabullet definitely helps. But not very much. Maybe even insignificantly. Actually I would like to measure it myself. The logic can be such:
Ultrabullet helps in hyperbullet (quite reasonable), Hyperbullet helps in bullet (also reasonable), bullet helps in blitz a little bit. Blitz can help a little bit in classical time control. So, the answer is, probably: "yes". It helps. But not too much. Or even almost unnoticeably.

The problem I can picture is that you basically repeat the same mistakes blindly without working on them, therefore you kinda reinforce them.

I play only 5+0. Then you can play normal openings, practice current theory, think in the middlegame and show some decent endgame technique.

This is just a long-period game compressed in a shorter period.

(Ultra) Bullet is driving fast through a scrap-heap, you'll learn to live from junk, that's all.

Ultra bullet is merely another means of acquiring a heart attack.

Ultrabullet is a pay to win, either live near the servers or get the best internet connections out there. From my experience from playing ultrabullet, it barely helps me. I just move random pieces in the hopes of predicting an attack and capturing pieces with premoves.
Also, checks mess the opponent up. Sacrifice anything you can for a check ;)

My Ultrabullet rating increased significantly when I started to make unsound sacrifices of pieces from the opening to destabilize the opponent's position and punish him if he is pre-moving. That says it all. The logic "It helps in Bullet which helps in Blitz which helps in Classical" doesn't work, because the only way it "helps" is finding some tricks that can work in longer time control as well. But there are no tricks you can discover in Ultra that will work in Classical game except when Classical (without increment) went into time scramble. But the latter effect on your Classical rating is negligible and the main point that it does not actually improve your understanding of chess. In the best case it just improves your ability to gain rating points.

And, believe it or not: if you get used to that premoving, idiotic tricks and so on you will possibly make your chess worse because you are thinking constantly about such crap. So be happy if you keep your level.