Twicefold. First, while manufacturing the explosive, we use some organized energy to arrange some stuff in an explosive form, with the expended energy turning into waste heat and increasing entropy. Then the explosive explodes, turning even more of the organized energy in the shape of chemical bonds, into heat, aka entropy.

Fusion bombs have the best conversion ratio from matter, which is the highest level of energy organization, into heat, which is the most entropic, with only some of the energy going into kinetic and radiation forms before also turning into waste heat.

Without explosives, it would take a tiny bit longer to convert that usable and organized energy into waste heat via other processes.

(the acceleration for the largest fusion bomb is likely on the order of less than 10^-400, but it’s something)