I've never thought of the Imperium as that transparently of a selfish place - I'd think the Imperium would maintain an image of "enlightened self-interest."
Holiday would probably be the time when nobles renew their oath of fealty to the Emperor, then demonstrate noblisse oblige; they'd be pretty much required (by strong custom) to donate some percentage of their income to charity within their fief (if they have one). If a noble's fief is in the middle of nowhere with all of 'population: 10' or something, most likely the noble will be "invited" (pretty much required again) to attend some Holiday party on the local Subsector or Sector capital (depending on which is closer/how highly placed they are) in which case they don't have to determine the charity event they sponsor and go to, they're probably assigned one by their betters. So it's probably not surprising to see baronets and so on serving "the traditional Holiday breakfast" to the homeless or the poor on Regina, then be recorded donating thousands of credits to some organization that offers financial aid / takes care of widows/widowers/orphans of Imperial Navy/Marines/Army/Scouts members.
Of course, some ex-Imperial Marine who was decorated for bravery and ended up with a Baron title might represent some TL1 world and get away with staying on his or her world; you can easily imagine the vids picking up on, "the 89 year old Baroness Gwyn Ganishuilli forty years ago found herself Baroness of Nek'tar, a poor TL1 world in the periphery of the Imperium. Although it doesn't yield the wealth that most viewers associate with fiefs, she still felt a strong sense of noblisse oblige. She established the tradition that during the Holiday, she would perform the traditional public service ... by joining the hunt of the Gantha, a traditional feasting animal and very dangerous megafauna, distributing inoculations to the children born that year, courtesy of a generous donation by Hortalez et Cie, as well as giving away holo-dee educational units. She does this for all of the fifty seven known tribes of the world over the course of a week, thanks to a ninth-hand Scout ship donated by the ISS and a grav belt..."
Same effect of lightening wallets, but looks much better to the public.
this started out humorous but I think I'll incorporate it IMTU.
