I think it's most likely testing the waters for a real offering. It's not that weird. Many colo data centers already have policies about hosting laptops because it's already something that happens. It just isn't common and usually isn't for hosting servers.
If the battery in the laptop is still good, it comes with it's own UPS. My MBPs haven't had an ethernet port in a minute, so do you have to supply your own adapters as well??? You could fit ~15 MBPs on their edge in 9RUs. That'd be an interesting looking rack. Not quite a blade chassis. It'd be rather boring looking as there's no blinky-blinkies
I didn't really think that any of what I wrote would be taken seriously to the point of needing a retort. I mentioned blade servers and knew rack unit measurements which as context clues would have suggested I was familiar with actual data center equipment.
And yet most homes and offices are full of them. Laptop batteries don't usually catch fire. At the colos I am familiar with (which have pretty strict rules, generally), you can have equipment with batteries as long as you regularly inspect them.
If you got creative with cable management you might be able to double up front and rear. It would probably be a PITA to manage but you could probably get some halfway decent density
Looks like they were proposing supplying usb Ethernet adapters, which doesn’t seem crazy, they’re cheap.
Hetzner rents you 42RU for €199 plus power and network. If we assume they can fill the entire rack, that's 4 9RU units for about €50 plus power and network.
If we assume an average power draw of 20W per laptop, that's 300W for each 15 laptop unit, or about €57/month in Hetzner's Finish DC (including aircon)
Not sure about network. A 1Gbit uplink with 10TB traffic (and €1/TB after that) is provided. Upgrading that to 10Gbit is probably similar to the €51/month cost for the same uplink for dedicated servers, so another €15 for each 15 laptop unit. Plus around €2/month/IP, but you can probably bring your own if you find a cheaper subnet to buy
So yeah, you are right that the math does not work out. But it is pretty close to break even. I think you can break even on this if you find a more space efficient way to cram them into the rack and don't pay yourself any salary