Rarely. Facing the USSR’s 10.3 lineup makes them useless. They’re also useless in their sim brackets currently. Your logic also applies to literally every vehicle in game.
Strong for the BR, sure, but low performing Sabot rounds and pretty average armor mean it’s fine at 9.0/9.3.
Kind of a default for most tanks, autocannons aren’t meant to frontally engage 90% of the time.
Mobility at the cost of armor
Maybe to HEAT, most kinetic rounds have no issue whatsoever except for poorly placed shots.
Justified 0.3 change, the 20mm is much better at killing light vehicles than the .50.
It has hilariously bad rounds and a higher-than-average reload speed, which can be disabled entirely by shooting the auto loader.
Ehh I don’t think that would be good. 750mm pen would put it at one of the highest penetrating tanks in the game. It would also be blatantly unhistorical.