Shrapnel-creating explosives is used for open ground. In closed-in terrain, blast explosives is always going to be more effective. That’s why the infamous “potato masher” grenade of the Germans was blast-only - it’s far more effective at killing people inside trenches and bunkers. The US used the WW1-vintage Mk.3 grenade for that same purpose up until very recently.

It can happen, but not at the rate you see in movies. Explosions in real life is far, far more brutal than they are in the movies. Blast waves can liqefy bone - something the writers of zombie media never seem to understand.