Eh? Why not? Use the scourge summon thing, I mean. It's not a bad idea to have mixed summons even if one or two does less damage, just for a variety of attack patterns. Unless it's something specific about the butterfly staff, heh.
... anyway, yeah, post-WoF things get... get. Once you start chipping your way into the content wall of death that is the boss fights. Currently mostly-puttering about with a summon heavy kit, too, just beyond the early game. Possibly I may have some sort of problem, because I have five summoning weapons, three minion granting accessories (and yes, if you haven't met them yet there are a good handful of these, just mostly seem to be post-wall), and two stationary portal/turret things.* Single target damage is kinda' iffy, but I can also more or less suppress anything that isn't a boss within two or three (of my) screens of the player character. Invasions are... amusing. The bar goes up and I don't see most of the invasion at all amusing.
Been setting up large hollowed out areas in pertinent parts of the underground (so far, hallow, spirit ice, desert, dungeon, and jungle), putting a few platforms (most with a chest or two, and I'm working to get safes out to 'em, to make it easier to shuttle drops between them and base). Pirate invasion, iirc, dropped the magnet thing, so I basically park myself in the rough center of the area, drop the two stationaries, then whip out the magnet and wait for whatever it is I'm trying to get to stream into my hands as things die in droves, hehehe. It's nice. Pretty passive unless I'm feeling frisky, but nice.
*
Eye of Odin (1; chain-lightning laser, chases, wall pass)
Something bark? Waking nightmare dungeon drop, can't see the whole description (and thus the name) without fiddling with resolution (1; melee monster, aggressive, wall pass, sits on what it wants to die)
Sun God Staff (1; pretty sure that's the max, also laser, but stationary over the player so it won't be diddling around a screen or three away while something's trying to eat my face)
Ghast staff (same as sun god, though it seems to spit out slow-ish homing shots)
Spirit staff (1; for essence trapping, AoE slow-ish shot, doesn't wall pass)
Eye of Storm (Probably the easiest to get "waifu" accessory I've noticed so far -- and gods, yes, the game actually refers to them as that -- spends most of its time off screen murdering things I can't see and littering the on and/or off screen with tornadoes)
Animus Lens (Forget where I got this, but puts two flames beside the player, one that does an eight way shot, the other that spits homing shots... maybe some other stuff, too. Can be hard to tell, heh)
Pearl of Enthrallment (This wouldn't have happened without cheating. The siren fight is moon lord level bullshit, possibly worse, and you have to kill plantera too, to get anything from it. Sits a good ways over the player's head, spews various projectiles at stuff)
Wispguard staff (Basically the animus lens, except in one sparkly cloud that sits where I tell it and shoots at things)
Shadow Sphere (Same as wispguard, except a circle that does contact damage and shoots purple debuff-things, both of these last a good long while, so it's nice for arenas or whatev')
What it all boils down to is my screen pretty much spends its time moonlighting as a danmaku stage, when my minions aren't just straight up offscreen culling the nearby monster count. I try to avoid being hit, but most of the time it's HP freeze or death, s'just too bloody much on the screen. And sometime that doesn't help me, either, heh. Recently got one-shot by a skeleton sniper, 400+ damage crit, full to death in one hit :V