I do it in every game I play, I helped popularize hammers and lances in the first MH when everyone thought they were underpowered, and I've been actively seeking out underdog weapons and characters in games like this ever since then.
I may not actually reach God Tier if they're actually terrible, but I'll still use them just because that's how I like to play.
They're actually pretty strong with the right set up. Deuce's radial normal attack is especially good. But of course, they're still overshadowed by harder/faster hitters like Jack, Ace, Nine, etc. Overall, Cinque and Deuce are very gimmicky fighters but you can always equip them with bomb type magic. Good luck using them~ I personally like using Deuce.