We were meeting up as a family on christmas eve instead of christmas day. I don't really see the point in that change.
Look beyond yourself and there are a lot of people who have plans from the 23th right through to the 27th or at least a few days regardless of the restrictions.
The idea will be that it will reduce the number of families mixing across the spectrum of days: e.g. Family A meeting B and C, then A meeting D and E.
All while B meets X, Y and C meets... For sensible people like yourself, there won't be much change, but I'd guess you aren't' the type of person it's aimed at.