I can't chase throught the smoke if I don't want to lose my tank since I don't have smoke or blitz to get away. Are we assuming the tank is supported? Because that makes it a different story..
Button was also advantage you get through doctrine (hard countered by doctrinal smoke) but it was nerfed becasue according to part of community it was OP becasue it led to losing a tank if not countered. Smoke is smiliar but in other way. It saves your tank if you make a mistake.
And attack ground is not always an option. Let's say you are 1 shot away from death, AT gun is almost ready to fire at you (you are 50-60 range from it) and the moment you hit smoke, AT gun loses target and befre you can attack ground, your tank will be out of the range.
I think the fact that he had AT guns supporting his tank (which can be counter with infantry), picked a certain commander, spent 30 munis, and applied the smoke in time makes the ability balanced. If its unsupported, the smoke works both ways because he can't shoot back at your tanks so they are able to close the distance and get right behind your tank unharmed.
If the tank is supported, then so should yours if you want a balanced situation.
"AT gun is almost ready to fire at you (you are 50-60 range from it) and the moment you hit smoke, AT gun loses target and befre you can attack ground, your tank will be out of the range."
And what about the shermans getting to block enemy AT guns with smoke while attacking or retreating?