You can break cracked walls with them or toss them at enemies to blow them up ... you just have to hit the bomb beforehand and make sure you're out of the blast radius once it goes off.

Personally, I almost never use them tho. If I want to mine large deposits of Zonaite or blow up an enemy camp, then I always have a "cannon" fused to a 1H weapon ready for that purpose. (use the "toss weapon" animation to aim and it will hurl an explosive while Link keeps hold of the actual weapon, similar to how the magic rods worked in BotW)