I don't really think there's any need for action... But:

If it's gonna be changed... a good reason to use karma instead of anything else would be that in spite of the domain change, user accounts will not be merged.

Showing karma for those who have a maemo.org account and not showing karma ("-" rather than "0") for those who don't might make people ask what this karma-thing is all about... how to get karma... which may lead to people opening a maemo.org-account... which in turn is good for the community: The maemo.org account is the key to further participation beyond the forum.