Custom difficulties are always super nice. I like games where I can increase the money I earn or my enemy encounter rate and also fix it as I play for grinding purposes or whatever.
I tend to keep everything fairly normal/medium level whenever I can but getting money faster is nice since I'm a fan of loot and fleshing out a collection book. If it's a style of game I don't really care for or I'm playing it again for the sake of story/speeding through, I will drop the difficulty. I used to play on the highest for achievements and trophies but then it feels less like a game and more like a job. No thanks!