When you have to manage 40+ at a time per location, crawling under the desk to try to finagle the power supply into a location that is frequently getting kicked, ripped, unplugged, etc is a real pain. I personally hate the whole external power supply brick concept for a desktop computer let alone when the ethernet is added to it. The ethernet on the power supply also makes it inherently difficult to tie a specific ethernet address to a specific computer unless you independently label each one and tie it back to the specific computer it was associated with; otherwise, all bets are off if you just toss them into a box and want to reuse them later. Finally, if a power supply goes bad or comes up missing, then you lose the ethernet for that device as well, so then you have to order a new one, assign a new ethernet address to the machine, reregister it on your network, and jump through a bunch more hoops. it is just poor design decision overall, especially for what I imagine is one of the iMacs top customers which is the education market.