I have been to a few that have been opened, most recently Atlantis in Reno.
I think the pricing is higher to reflect the additional staffing costs to serve buffet style. I don't mind since I miss buffets and still can get them comped for the most part, although I find it difficult to communicate with the servers- between the plexiglass separating us, and wearing a mask and them wearing a mask no one can hear each other and you end up having to point to things until they get it right.