I'm going to make an uneducated guess for something about servers. That's the power cable to a motherboard right, but only a few ports. So...something where you need more than one motherboard but only one board needs full power. First thought is servers and powering extra RAM.
@Edelwood Someone else pointed out actually that it's probably for getting the PS_ON (the "turn on full power" signal) to multiple PSUs hooked up to a ton of GPUs for cryptocurrency nonsense. Servers have more professional multi-PSU solutions, I imagine
Aha! So I had the right idea but I was backward about it. Multiple PSUs to one board rather than one PSU to multiple boards. Still that cord setup fills me with the same emotion as seeing a a 120 volt power cord that terminates in a USB plug
@Edelwood yeah putting 120/240 V AC on a flash drive's USB connector is probably going to destroy it pretty well
some data might still be accessible if you open the thing up and use an atomic force microscope or something but in all likelihood you've destroyed the chip
@Felthry
I've heard they have some merit as testing items (making sure hardware is, in fact, protected from power surges from more than just the PSU) and also self-destructing equipment for security's sake