Indeed, between bikes made exclusively for mountain biking and road racing, the rim differences are likely to be more obvious, but when you get into areas where the distinction is less obvious, like touring and cycle cross, then it's less clear.
The advantage, is that with slightly more consistent wheel sizing, 700C rims, and other components, are available in a wider variety of options, unless you want 26" bits! (which of course may be the case for women, with generally smaller bikes and frames).
It is interesting that they are using a single chainring, although this seems to be more a function of the relatively short course, with no long uphill stretches, where more gears could be useful. I guess aside from the weight savings of only a single chainring on the front, and so no changer, lever or cabling, the bike is also mechanically simpler, so less to go wrong, which is an advantage where there's only a very limited ability to deal with mechanicals.
