Aha, makes some sense. I guess it's rounded up so that anyone with karma >1 gets a voting power of 2?
In the past everyone had a "voting power" of one unit. Now most people will have more than that, and some will have quite a bit more. So scores on posts and comments will be *much larger*, at least if the amount of voting on them is fixed, and the very first downvote a comment gets can bring its score down to levels formerly only seen by *exceptionally* stupid or spammy or otherwise horrible comments. Old comments will mostly have more "moderate" scores -- apart from any that get discovered by new superpowered users...
Unless, of course, you retroactively recompute all past comment scores according to the voters' karma -- and then presumably recompute that karma, which may be several times larger as a result, and iterate to convergence. That will substantially inflate everyone's karma.
Both of these outcomes feel a bit weird to me.
I thought that instead of everyone having to create a separate post for their first impressions, it would be more convenient to create a single post for this discussion. I'll post my own here soon.