Yeah, that makes sense.

My question then is: why make it a ritual rather than just a holiday party? Why not: "Every year, we [my friends/this meetup group/whoever] get together on December the whateverth and have a holiday party! It's tradition! Yay!"? That works as a Schelling Point too, no?

Of course, at this point, "why" is partly rhetorical, as daenerys and Raemon have more or less responded.