Those guys got turned into collapsing skeletons by a bomb so powerful it didn't even need to explode to turn them into dust. It kills human clothes, human flesh, and absolutely nothing else. It didn't even get goo on that banner. When you saw that nightmare bomb go off, you knew Spider-Man was doomed. What's the melt radius on it? Can Spider-Man jump away that fast? Spider-Man is going to die!
Except he obviously didn't. Luckily for him, the Goblin is polite enough to never use that super skeleton bomb again in the movie. For the final showdown, he instead goes with a totally ordinary kind of bomb. Except we shouldn't say ordinary. He used a bomb that absolutely exploded right on Spider-Man's face and didn't kill him.
We mean, this is best-case-scenario for a grenade. If THIS doesn't kill a Spider-Man, why even carry it with you?
The crappy firecracker bomb looks like it's about the same size and weight as the amazing skeleton-making one, so why bother with it? A classic explosion is always handy, but this grenade seems barely able to cleave through a spandex face mask. It's not like you could use it to blow the door off a bank vault. If it were a regular, not-exploding ball of metal it would have hurt Spider-Man more. Here's his face mere days after it went off right on it:
This is not a face of a man thinking, "I sure wish that grenade hadn't gone off on my head earlier this week!"