Satoshi's identity is important.
For a start - Remaining anonymous is a big bump to their credibility. The person(s) acted and interacted publicly, collaborated with other people, and no one knows who they are or are keeping quiet about it. That's hard. Very hard. You need to know what you are doing to accomplish that. It also requires discipline and, likely, planning.
Secondly, the global implications. What if undeniable evidence breaks that points to a nation state? What if Mike Hearn is discovered to be Satoshi? GMaxwell? Etc.