While there's plenty of answers to the question why nobody realizes Clark Kent and Superman are the same person, a question that I haven't seen the answer for yet is why Superman keeps the Clark Kent persona around in the first place. My understanding is that in the olden days Superman was genuinely a mask the man Clark Kent wore, but those roles seem to be reversed with modern interpretations. So why does Clark Kent still exist? Does Superman like journalism so much? Does he just occasionally need a break from superheroing? Does he want a human identity to help him stay grounded?
What exactly is the current canon rationale for this?