[Imp]

I think you will find the wide range of MGs & ATGMs with transport is so other formations can use them so they are needed due to the way the game is structured.

Example if you buy say a BMP Co Plus it has MMGs &or ATGMs attached.
The easy way to do this is to attach a pre built formation so it uses the MMGs/ATGMs of the same vehicle type in effect attaching that platoon(s)
Companys consist of a leader followed by platoons but the platoons need to exist so it can use them.