There is a great debate whether the Rocket Launcher or a Grenade Launcher is an overall better weapon. But it all comes down to damage stats -- where Rocket Launcher wins significantly.
Yes, there are six rounds of ammo in the GL, while RL has only one. But when you need to smash the opponent's buildings into smithereens, you want to do the job as quickly as possible, and for that RL's one-shot is more than enough.
What is your personal top 5 of weapons in Fortnite's Battle Royale mode? Let the world know in the comments below.