A couple more questions on tanks

[AlienXXX]

Hello all fellow WinSP / MBT players

perhaps some of you can help with my questions.

First. AI fires a lot of rifle / sniper / MG against tanks. Is there any point?
There is a chance of causing suppression to the tank, but seems dumb as it is more likely these infantry units get hurt from the tank's return fire (unless drawing fire was the idea in the first place).
Realistically tanks had peep holes and man holes and these were often open in WW2 (tanks did not have aircon back then). So does infantry (with no proper AT weapons) stand a chance of scoring crew kills against tanks?

Second, vehicle crews seem to carry a standard issue of pistol + grenades + smoke grenades.
Modern tank crews will often carry automatic machine pistols such as Scorpion Vz61. So far I have not found this sort of weapon on vehicle crews, they all seem to carry revolvers or automatic pistols.
Is there a reason machine pistols have not been implemented in MBT ?

Thanks to all