Yes, for Virtual Power, this is SUPER important. In short, Virtual Power takes your wheel speed and known trainer (as entered into the app) and converts that to an estimated power.
- If you removed the pressure entirely, but still pedaled it, you would be getting power data, because of the wheel speed. This would of course be totally inaccurate.
- That is an extreme example, but meant to show that wheel speed is the way the app estimates power. So having very consistent bike tire pressure and trainer roller pressure is essential in giving you worthwhile data.
Until you make a serious effort to control those settings, that is in question, IMHO.
- Only in the sense that you may be getting inconsistent tire and roller pressure.
- The Blue Matic is a fine trainer for what it is, AFAIK. I have not heard of major issues.
- Have you confirmed that you have the right trainer and trainer resistance setting applied in the TR app?