I believe the telco’s did dc power for years so I don’t think this anything new. Any old hands out there want to school us on how it was done in the old days?
Every old telco technician had a story about dropping a wrench on a busbar or other bare piece of high powered transmission equipment and having to shut that center down, get out the heavy equipment, and cut it off because the wrench had been welded to the bus bars.
Note that the rack doesn't accept DC input, like lots of (e.g., NEBS certified) telco equipment. There's a bus bar, but it's enclosed within the rack itself. The rack takes single- or three-phase AC inputs to power the rectifiers, which are then attached to the internal bus bar.