It really depends on the construction of the wall. Outer walls made of stone will be rather less effected by a HEAT charge than inner walls. The main exception would be HESH warheads but they are rare these days.
Besides in WWII a Panzerfaust was more use against enemy armour or MG positions than in simple demolition for which the Soviets were well equipped already. Why use an M16 mag to open a bottle of beer when you carry a bottle opener anyway. Especially if you might need your M16 mag to work properly later on.