For consistency purpose, and from a personal perspective as an avid YouTube consumer, I would suggest still uploading. Not everyone celebrates Christmas and even some who do still watch YouTube. Not to mention you could have people from other countries who watch YouTube even during the holidays. This is the time of the year I have a hard time finding content to watch because most of my fav YouTubers take a break. I personally find this annoying but I understand why. I watch a lot of YouTube, it's in essence my form of local TV channels.
Now, there's always a chance the numbers won't be great. But then again you could find yourself in the unique position of being seen as a content creator who can be counted on to provide content even when everyone else is taking a vacation.
The trick, however, is to plan the video way ahead so you won't be making content right before the holidays. Make the video early in the month, perhaps a best of or gag reel of your content from the past year. Something simple to make that you can set up to schedule to publish weeks ahead so it can just publish automatically and all you have to do is just check the comments at least the first hour then enjoy the rest of the holiday.
Hope this helps.
