
Fake explosives put out a lot of flame and last long enough to get a good shot on film, whereas real explosives put all their energy into the explosive force and are hard to film.
www.youtube.com/watch?v=nqJiWbD08Yw
Tom Scott did a video on exactly this which I have posted above
( , Wed 3 May 2023, 14:06, Reply)

but I think a Molotov cocktail also looks like that.
Slow motion Molotov cocktail video:
www.youtube.com/watch?v=lfvceHUBWnU
( , Wed 3 May 2023, 15:23, Reply)

whereas this thing set fire to the roof below it.
( , Thu 4 May 2023, 22:21, Reply)