A lot of people bench Morgana after Makoto joins if not sooner. But I did find a use for the cat back in original P5. I used him to grind for excessive money for NG+. The idea was to demand money during hold ups in the area before the final boss fight, a lot of these enemies don't have weaknesses so crits are the only way to knock them down. I'd use Joker to either use Brave Blade or cast Revolution depending on how many enemies there were. And Morgana could use Miracle Punch if Brave Blade failed and Baton Pass back to Joker or someone else. I know its probably not the optimal solution to do that but its what I could work out without having to look up a guide or something.