Mouldy, sometimes it is not about getting out what you have anyway. The DCs are already excited by the day and overexcited by the forthcoming day - and need an opportunity to wind down for sleep.
In my case, not only do we have that general need to unwind, but DD has ADHD and aspergers, so highly excitable and a huge need for routine to be maintained. As in, it took me 3 years to slowly pull back from reading her to sleep nightly and only then because she accepted audiobooks instead a few nights a week.
So, yes, we have PJs anyway, we have hot choc anyway, we push for baths anyway (and often they are lush bomb ones filled with lavender to get her sleepy!). But the whole ritual of getting out a small (slightly larger than a shoebox) cardboard box with new PJs, a special hot chocolate and the bath bomb, as well as the old favourites (TTNBF book, her stocking, the Christmas plate and cup from the cupboard) kept until 24th so they are still "fresh", doesn't mean it is a waste or an extravagance.
But it does "signal" to DD that the playtime is over. We are doing our quiet ritual of thinking about the year and loved ones not here anymore. And then we are gently moving towards bed.
We don't have massive PILES of gifts either on Christmas Eve or Christmas Day. Well, there are but that's because we have large families - DD gets a main present and her stocking (which is 12" long - not sackloads) from FC, there has always been a present from us under the tree (something eminently sensible like clothes that are needed usually) and we give her something fun for her birthday too (26th).
She's had a dressing gown as a Christmas present on more than 1 Christmas! Most of the books and DVDs, gathered over many years, come out earlier but Twas the Night Before Christmas is one that, again - routine, we have always read for the first time in the season on Christmas Eve.
It has never spoiled the magic in our house, it is part of the quiet magical time when we have our reflection as a family, and then DD sets out her stocking and treat for FC much calmer, and enjoys a good splash in the bath on the way to bed.
We are also a household where everyone gives presents, and FC doesn't bring the lot. And even that we, as parents, give something - small but not leaving DD out of what we are giving to everyone else.
Every family has different capacity and desires to give material things and non-material things over the festive season. It is absolultely not worth getting into debt for, nor putting others under pressure with the "Oooh look how high the pile for my darling precious Snowflake is and how much I love her based on how many things she has to open". That is absolutely NOT my message. But if a family can afford it and want to, and hopefully it is part of an overall giving to the family and wider, then why do you have a problem with it?
Some people want to make a big splash, others want more restrained, while there is every shade of variation in between.
Can we not let everyone decide themselves where they want to be on that spectrum without slating them for it?
Afterall, it is the season of goodwill to all and peace to all men. And this is the Christmas board where the spirit of the Christmas season lives all year round.
(OKay, that last bit is slightly 
, but I do mean the underlying sentiment).