Really? I am just noticed that my vet 2 tank with accuracy bonus starts to hit infantry more often.
Okay than, if relic really wanted to make comet more effective against bigger targets why it recieves accuracy not penetration?
Accuracy only affects "heatseeking projectilees" that will follow the target anywhere it goes. This includes panzershrecks; it also includes small-arms fire which, generally, have a very large accuracy values.
If you take the Comet, and stack all the accuracy bonuses on top (commander & vet), you get about 6% accuracy vs infantry at mid-long range. However, from experience, you must have noticed that the Comet hits a lot more often than 6% of the time. That's solely because of a combination of very good scatter with decent AoE.
This means that the accuracy-based part of the hit-roll is unimportant.