When doing non-CG crash for movies, they often stuff the vehicle with explosives for a more spectacular result. They know it's not realistic, because they take the decision to add all these explosives.

Now when reality gets influenced by fiction, ISIS actually used bombs that make a lot of flames, more than necessary for warfare, just to make their propaganda videos similar to the Hollywood movies their recruiting targets have been watching all their life.

Perhaps to make it look worse on tv to get coverage .

I am sure recruiting videos could just as well use CGI if they wanted to. Likely anyway does, skifull editing and manipulation are required for any propoganda content anyway.