It's not the "same moment" as they're skated days/weeks after the original date. So the skaters aren't in the exact same physical/psychological moment.
BTW: timezones. If you want to make everybody skate at home, there are skaters from China, Canada, Japan, USA, etc. If they all skate at the same moment, because I assume you're not having the judges on a videoconference for 24 hours, some of them skate early in the morning, and some others late at night. Everybody who has followed skating for a while knows that the skating time affects a lot the skaters' performance.