Depends on the kid. It’s not fun to all kids.
If my parents had gone to elaborate lengths to insist that Santa existed I’d have been confused, as it didn’t fit with what I was learning about the physical world, and Is have felt unease that they were trying to persuade me of something so bizarre. It wouldn’t have been a positive. TBH they did try but it was always obvious.
I loved Christmas anyway though and I still do. I loved it because we had a house full of family having a great time and being just pissed enough to be really fun. That’s what was important to me, not who delivered the presents.