They buffed it because it was UP and still has no role beside the occasional m3 hunting.
And one of the key reasons why the ostheer is in such a bad shape is that this unit is performing at all as a vehicle hunter.
It has no role because meta isn't M3/M20/Dodge/UC spam/rush anymore. Its sole purpose is to counter light vehicle start and to give vision with its vet. Axis players want to buff it by lazyness, having a unit that counter early inf + early vehicles for a really small price because they don't micro their squads.
Ironically, the free upgrade killed even more the meta it belong to since nobody is going to spend fuel on a M3/M20/Dodge to be automatically counter by a brainless 221 coming 3 minutes later.
You want an early AI vehicle, build a 251 + flammer upgrade, or whine better/stronger/harder to have the upgrade for free like you did with the 221.