The lances have poor crowd control, I only ever bring them if theres something like hectors and stronger. good weapons tough.
Also you are forgetting the iddun's (or any electric weapons) factor not shown in the stats: the ricocheting. It seems the enemy hit by it doesnt need the actual bolt to bounce off its body and hit it again, it probably hits twice on the first contact.
This already happened since the second game, I remember taking on mecha godzilla and being surprised at how fast he died with a weapon that technically should had take more time to kill it.
sacred lance is pretty good crowd control - it's got a bit of a spread, but it depends on your style. idunns stun lock so that's their main draw for me, but they're an anti bug weapon through and through.
idunns reflecting is cool, but that's not much help against single targets like the wasp nests.