so why would you ever get this over an ostwind?
and did you say early? by the time i get to my second or 3rd tank this thing becomes available.
Because you don't need to tech up to tier 3, which saves a lot of money.
And yeah, if you consider a infantry heavy strategy, where you go for Tier 2 with couple of PGs and your opponent tries to counter that with sniper + infantry of himself, these StuGs gonna hit your opponent really hard as he is only investing in anti-infantry.
And even if you get a P4 before you reach 3 cps, the StuG is still an awesome support unit, with quite a lot of potential to soak up dmg and snipe infantry.
Btw, if you played CoH1, you probably know the StuH42, which came at 4cp. It was even more of a situational unit for most of the time, but it was by no means useless. You have to play it right and force your opponent into a lot of anti-infantry, so that you can surprise him with a tank that costs almost nothing.
On another note, the least you will do with the StuG is to force your opponent into building expensive anti-tank units/weapons. Considering you almost pay nothing for the StuG, this is a really good trade for you.