You can also drive though the smoke. If you say you'll hit paks behind it then you could say the same thing about no smoke. Smoke is an advantage that you get through a doctrine isn't it?
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.
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.