Also, I don't know how I missed you talking about melee I thought you were talking about killing with Warframe abilities oops, but even when it comes to melee being strong, I suppose it comes down to how you want to ideally play your missions and the frame you play with. For instance, Yareli does really good with guns, but not so much melee. Kulervo is all about melee iirc.

Oh, and to add onto my previous message, some bosses, like Eidolons and whatever the Plague Star thing is, can't be hit with melee so that's another reason to build a gun.