Prepping a full RPG system for my class this year... am I overthinking the "buy-in"?

I’m currently setting up a whole RPG gamification thing for my 4th graders before the new term starts here in Korea. The plan is points for participation, customizable avatars, item shops—the whole nine yards.

I feel like the kids are going to absolutely lose their minds (in a good way) at first, but honestly, I'm a bit worried about the long run. I don't want it to just be a "cool new toy" that they get bored of by week 6.

For those of you who’ve integrated deep gamification (not just stickers, but like actual economies or RPG elements): How do you keep it fresh for the entire year? Does the novelty wear off too fast?

Also, any advice on how to prevent it from becoming just a "bribe" system where they won't do anything unless there's a point attached?