Honestly, I would actually be thrilled if my son had these kinds of math enrichment projects rather than having to sit around waiting for everyone else to figure out something he either already knew or figured out in two seconds. I have been trying to get enrichment for him, have been told he is receiving it, but I have seen no evidence.
Is it the assignments that are the problem or the teacher's insistence that she can't work on it at home? It sounds like your dd is happy and engaged in the projects, she just needs to be given the freedom to do it her way.
I do actually think that creating a game is learning if done right, but perhaps the teacher isn't quite following the goal. The "challenge" is designing the game, the strategy, the rules, etc., not constructing the board and the pieces. Designing games is a great opportunity to show creativity, logic, and mastery of the concept. But it sounds like it was not put into practice properly.
So, I don't think it is busy work, and it sounds like the teacher is really trying, she just doesn't quite get the purpose.
Maybe you could ask the GT teacher/coordinator to talk to her? And I would ask why she can't work on the project at home? I don't see any valid reason why she shouldn't be able to if she wants to.
