This means no sales, no themed merchandise, no decorations. December 25 and most other day are treated just like any other day for all stores malls, restaurants, ect.
You’d still get non religious holiday events like mothers days, or independence days.
What whould change?
I always considered it the mid-winter celebration. A time to break into some of the stored food (sugar-preserved fruit anyone?). Basically a way to raise the spirits since autumn harvest was long gone and it felt a long way til spring.