If you've flanked with the infantry squad, a two model grenade blast will knock it down to two models. Two model MGs don't have good chances of packing up and running.
If you try to kill it frontally with a grenade, it probably won't work any more.
Most time MG has infantry cover
Now——that's flanked enemy squad maybe kill my MG squad with grande,I should move my MG
Limit 2 model——that's grande can't kill my MG,so keep fire suppression enemy squad,and my other infantry squad can deal flanked squad