Well, if that's the point you're going to make, then I'm going to assume you've, at the very least, never gotten past the Lunatic Cultist. You gotta understand that a number's just a number; it's how that number is utilized that matters. In each weapon's case:
- The Last Prism deals EXTREMELY rapid damage in an EXTREMELY wide area; and when its beams converge into one, they cover a comparatively small area, but they deal HEAVILY-increased damage, which is paired alongside the rapid hit rate. Before you say anything, this is a weapon you get from DEFEATING the FINAL BOSS, meaning it's GOING to be supremely powerful (it would EASILY out-damage the Glowva Rod). Of course, your Mana consumption increases alongside the intensity of the beam.
- The Nebula Blaze and Arcanum are gotten from fragments obtained by defeating enough Nebula Pillar enemies to get to and destroy the Nebula Pillar itself. You can die at any time during the Celestial Events, but your progress on a Pillar is retained between lines; these pillars are also fought BEFORE the final boss, but after Plantera (and the Lunatic Cultist), just to give you a perspective on the amount of challenge required to get these things. Now to give you a perspective on just how the Nebula weapons attack:
- The Nebula Blaze rapid-fires damaging blasts, which have a 20% chance of doing tripled damage and having increased velocity. The projectiles also home in, to a degree, and deal decent knockback. The mana cost is pretty high, though, and you'll chew through your supply rather quickly with this.
- The Arcanum deals less damage and fires slower, but each projectile hits twice and explodes into a bunch of smaller projectiles that rack up the damage even further. They also home in (a lot more strongly than the Nebula Blaze, I might add), and they also eat up a lot more Mana per usage.
They all hit for less damage PER HIT (at least, right away), but they also DEAL
a LOT MORE HITS. They're all the
opposite of the Glowva Rod, which is extremely slow to use, but deals significant damage per hit in return.