look man i know very well that i am a casual player and that you have obviously sunk way more time into this game than i ever have or will, but garrisoning troops isn't solely a utility ability it allows your troops to fight with more protection.
It doesn't mean jack if you can live longer if you still can't kill a thing.
Vet3 con buff is best example here. They are more durable, but they are still just vet feeders and cappers.
You'll simply have combat crippled squad on field longer while you could use a proper infantry or ATG for not really much bigger cost, who actually does the job its meant to do.
There is no redeeming factor for M-42. It would still be underpowered even at 160-120 menpower as it would still eat your pop cap rapidly without giving much in return.
This is the case of utterly crappy main stats in relation to its cost, not any utility.