Sometimes power supplies have USB and RS232 interfaces, what is the reason?
In this video of eev blog, david jones was doing a teardown of one which has rs232 and usb interfaces..
This would typically be to allow them to be remotely programmable from a PC, e.g. this TDK-Lambda Z+400 supply which provides USB, RS-232 and RS-485 interfaces.
Programmability is very useful in setting up automated testing. Sort of like having a DAC with a large current capability.