Yes, I think people tend to underestimate the chaos some malicious actors could do by even "just" coordinated litteral burning of stuff. Think a dozen people with cans of gasoline and matches spread over three different suburbias in a city, wooden churches or other wooden buildings of interest. Or simple firebombs on underground subway plattforms. Would probably not be that lethal but I guess very frighting.
(Not even mentioning explosives etc, but this could probably be prepared in like an hour by just purchasing supplies at local gas stations in any country)