Prince has a humorous streak, David Bowie has a humorous streak, The Beatles had a humorous streak. Humourless music is not nice music as far as I’m concerned. I’m not trying to compare Metronomy to Prince, but I think people often forget that being humorous and being cool are not mutually exclusive things.
I only really think it’s important in as far as it allows you to see what you do from a different, less self-absorbed perspective. There are countless musicians out there who take themselves way way way too seriously.