It would be great for running in general as it would give runners twice as many Olympics they could compete in. This would allow some people with great range to become huge Olympics names. Like everyone knows who Phelps is just because he has a bazillion medals even though swimming is more boring to watch than running. But way less people know who Bekele is. If Bekele had another 3 or 4 gold medals he'd be much more well known.
It would also incentivize people having range instead of specializing, which would create more matchups between people who currently don't race each other much. Marathoners vs milers, etc
It would also create a distance running related team sport.
It could also be more compelling because the weather would make predicting the winner much more difficult. Imagine a race in cold, icy conditions vs muddy wet conditions. Often a different person would be better depending on the conditions and you wouldn't know the conditions until right before race time.
The more I think about it, the more I can think of good reasons to have XC in the Winter games. I can't think of a single good reason not to do this.