FAE contain explosives in solution, that's what gives them their punch. It's the contained explosives that result in the whole disbused mass detonating. Straight fuels just burn, there's a flame front from the ignition source. FAE detonations are like knocking in an engine, they don't have a flame front that progresses from the igntion point as normal burn does. The knocks in a car engine are not smooth release of energy with a pushing force, but instantaneous release like a hammer blow.
With FAEs, is the stuff gets ignited before its disbursed, it just burns like napalm and doesn't explode.