Having personality traits in common is a great thing, like if you share the same sense of humour obviously that's going to help you.
Conversely I think having hobbies and interests in common isn't really helpful at all. In fact, I think it can be unhelpful sometimes because if you have all the same interests then you don't have things that you can do on your own, and whatever anyone says I think people need space and to be able to hang out with their friends away from their partner occasionally.
Yeah, this. You need superficial differences to add spice & fundamental similarities to avoid resenting each other in the long run. Superficial attributes in this context are things such as political outlook, cultural background, race, nationality, interests, & hobbies. These can be as different as you want. Fundamental attributes include need for pleasure (sex, drugs, sleep, food, etc.), ambition in the broadest sense, degree of openness & honesty, level of individuality, & attitudes to others' faults. Big differences in any of those and the relationship is doomed in the long term.