Correct Thaxos, in real life troops still used flamethrowers in wars, even after witnessing their friends die from it blowing up. The same thing would happen if it was a jetpack, you're drenched in burning fuel, a slow agonizing death. There is a difference with DetPacks, it's a faster death. So if you are going to die either way, I'd rather it be so quick I may not even realize it. And even if I have neither a jetpack or a detpack, if you are shot in the back it's still most likely fatal.
Well one functionality in universe purpose would be anyone would think twice before shooting me in the back!

Also it's possible their detonators did not explode because they have to be primed. Some real life explosives are safe to be dropped, shocked, and/or burned before they are primed.
But like I said before, the main reason I am doing this is additional storage space. I am making my armor as light as I can so that movement will be easier. While in universe this means I am less protected from explosives, it also means that after I set them, I can run like hell! 8)