Only purpose of 221 is to upgrade to 223.
Its firepower is decent and its going to 1 burst kill sniper(2 on the move).
As you said it yourself, its purpose can be a relatively cheap potential counter to snipers (and HMG spam) that OKW currently does not have. Bully Infantry Sections in cover or defend flanks or remote sectors.
Given there is puppchen in T0, it shouldn't have any meaningful performance against lights.
This argument doesn't really make sense. It is supposed to be an alternative. Should we remove DShK and M42 from the game too because Soviets already have HMG and ATG in stock line up?
I can't see a single logical reason why 221 would exist other then give OKW something to build in early game that isn't volks.
That's exactly the point imo, to give OKW a viable alternative (together with new JLI) to actually have more than 1 viable opening strat. Diversity is good for the game's health.