For the extreme opposite of that, Google famously trolled everyone 10 years ago by announcing that every one of their servers had its own in-chassis 12V battery:
It’s true! I wrote software that upgraded firmware on every one of those batteries without frying them up (most of the time). There was a public paper/talk on that few years back
That presentation is pretty interesting, including Google inventing their own "Switched Tank" DC-DC converters because the existing ones weren't efficient or reliable enough.
And Facebook had small UPS/ATS units at the end of each row. Not sure if they still do that today it was like that when I walked through their datacenter. They did that for the purpose of power efficiency. They lost far less power by having many smaller units.
> A data center typically spans four rooms, called suites,
where racks of servers are arranged in rows. Up to four MSBs
provide power to each suite. In turn, each MSB supplies up to four 1.25 MW Switch Boards (SBs). From each SB, power is
fed to the 190 KW Reactive Power Panels (RPPs) stationed at
the end of each row of racks.
They specifically called em out as UPS and talked about the efficiency improvements over having a dedicated UPS room. I don't remember the percentage numbers though. It was orders of magnitude less power loss. It could be they ditched all of that hardware by now. This was some time ago. You might ask some of the old timers in the DC. They probably have pictures of the hardware.
It sounds rather wasteful to have one device generate mains voltage AC power, only to have another device transform it to lower voltage power and rectify it.