Does not take much to mangle human legs.

Shrapnel is effective as a flying projectile mostly due to its jagged edges (vs curved shape of a bullet).

The concussion of an explosion can kill. It damages voids (empty spaces) in soft tissues causing massive trauma. Peoples lungs fill with fluid, other organs fail.

The jugs had straight home cooked HE in them. The bottles were sometimes a trigger, many times filled with fuel to add to deflagration of the event.

Fireworks (not the kind you can buy) have no (solid) metal in them for the most part, and they kill people all the time.

Long story short, you dont need a metal pressure vessel that fragments to kill with an explosion (detonation). Overpressure is a motherfucker.