Actual use for 2 weapons

Genuinely curious at this point with the OBT wrapping up. What uses in most hunts are there for the 2nd weapon equipped (outside of bringing a 2nd element for double monster hunts) From my knowledge, most weapons don't all want the same skills. I know I like to try a different weapon for a first time play-through and planning on starting with Gunlance, but from what I know there aren't really any other weapons looking for the same weapon skills/decos (Maybe Chargeblade some).
Outside of element are there many weapons which would benefit from having a weapon swap without being able to also swap armor mid hunt?