I agree with everyone so far; I think she looked good with the mask, it makes sense for her to have a mask, and I liked that the mask served additional functions (showing Usagi things happening elsewhere, showing monsters' true forms). I really hope it'll get included in an adaptation one day, but it probably never will
I feel like the mask would be cute if she were a solo hero but as a group uniform it would look stupid. I also feel like it's unnecessary because I feel in my head canon that her transformation has a built in cloaking mechanism which is why nobody recognizes her.
I did think her mask did look pretty in fact the manga looks of Sailor Moon were actually what inspired my design for Hina Kusaka as Sailor Sun in my fic. However if she got to have a mask then shouldn't the other Senshi get masks as well? I mean I suppose Sailor Venus could use her mask from her Sailor V days and maybe Sailor Mercury could use her goggles. Then again maybe they could have all used their masks from their concept art in the artbooks. It also makes me wonder what the Outer's masks would be if all Senshi had masks.