To be honest, I have no idea how 4-5 squads with PTRSes destroying weapon is different than Grens blob killing crew and stealing or destroying it with pzschrecks. Same for OKW blob killing crew and then destroying weapon with volks. It's excatly same result, just OST and OKW must make 3 more clicks to destroy weapon.
The difference is that in grens (or volks) approaching maxims/50 cal. If u are quick u have the chance to retreat but with ptrs, bam 1-2 shot as soon as they spot u, mg is evaporated. 2nd, comparing the accuracy values of shreck with ptrs the probability of shrecks hiring and destroying the mg itself is not comparble with ptrs
plus, in most cases a mg is not alone and there are grens/volks/cons/rifles around it, and when you come for an assault/flank, usually when you aim to take out the mg, if there are no ptrs, mg gets decrewed and after the assault/flank is pushed back you will have the chance to recrew it but if you come with the ptrs blob, all the support weapons in that area including mgs/mortars/ATs get destroyed by 1-2 click
AND YOU CAN DESTROY THEM TOO QUICKLY AND I'M SURE YOU KNOW TIME IS VERY IMPORTANT, YOU CAN DESTROY ALL THOSE IN A FLASH OF A LIGHT BEFORE YOU RETREAT YOUR BLOB