Well, it is statistically zero sum game - some bills will be rounded up, and some down so the balance would be ~zero. In some countries lowest value of circulating coin is much higher than US or Canadian cent (Sweden for example where the lowest is 1 Krona = 15 Canadian cents) and nobody seems to mind as they round bills down (0,50 and less) and up (0,51 and more).
RE: Why I collect copper pennies and you should too.