There are arguments for both sides as far as displaying native steem rewards vs dollars.
People can relate to US dollars, so it's an incentive to attain more dollars instead of something nebulous like steem fun dollars, even though they are worth more. So, I think dollars is a good thing to display to people new to steem because they see there is real potential if they create content other people appreciate.
Unfortunately, I think it creates more of a perverse incentive for people who are here to feed their greed. The same symbol will mean different things to different people, and there isn't a way to have it mean what you want it to mean to everybody.
I think there's a possibility that switching it over to a steem denominated amount could be a better idea in the long run after steemit has reached a critical mass because by then you won't have to wave dollars in people's faces, they will be here for the steem power.