There’s really only a window of time that I used MGs for their actual purpose and now that I have coalition echelons unlocked, I never use them. For reference a 3 mg 2 sg echelon costs 600 ammo (max restock) while a coalition costs a fixed 360 ammo regardless of who’s in it. Plus, if a map has a low high strength enemy (<170k combat effectiveness) and a heavy heliport, I can drop down my tank and slowly damage them before attacking with my coalition echelon.
Also, Beluga (M16A1 coalition) doesn’t help as her symbiosis ability increases armour of all active coalition units by 20% for the duration of the map while for G&K echelons increasing evasion by 30%.