I notice that the DEWs cause explosions on their targets, so that leads me to think they are targeting specific components on said targets, and overloading the circuitry or heating some explosive materials to their combustion points. But I noticed a distinct lack of melting of anything in this video.

Rubber tires however, especially when surrounded by fire on all sides which is being blown (think when you blow a fire it burns hotter) by 90mph wind gusts, do burn hot enough to melt aluminum wheels.

And yes, they also burn hot enough to incinerate this straw man!

edit- forgot to mention that these DEWs are for use on objects with heat signatures and also used in clear conditions. All the smoke and dust would refract or dissipate the beams, would it not?