What is the purpose of Warheads besides a trophy? Ok and of course killing the bad guys occasionally.

By detonating them, you open up blocked off areas. It would be pretty strange if you entered the Divide and the road from where you start all the way to Ulysses temple was clear of debris after the whole underground detonation disaster. So they added areas that were blocked off to have the map make more sense, the warheads just let you unclog those areas so to speak.

day go boom boom mang

some of these uncover the path forward, some for weapons and ammo and some just for the trophy challange