Personally I wouldn't say character customisaton is my favourite part of most video games but I am still an absolute sucker for character customisation and I love creating my own characters. My favourite games are the ones where you can keep evolving your character as you progress with more customisation options through perks, abilities, skills, weapons, armor or just nice clothes.
I also agree that a game that fully focuses on character customization can be a lot of fun because character customisation just rocks. And this game definitively stands proof of that.