I was also wondering why they covered it up, especially so tightly. Only reason I could think of was to create some sort of "unveiling" but then I realized that does make much sense. Either way, with how far the walls are pushed back now, and with only tiny details left, I think it's only a matter of about two weeks now. Exterior looks finished, they must be focusing on interior now.
What I find interesting is how incredibly fast the facade for Luigi's is going up. Was it built off site of were they just that fast?