This is kind of the general equivalent of letting someone sign your checks. I don't want anyone else signing my checks, and I don't want anyone doing anything else on my behalf.
No _startup_ CEO's time is so valuable or so scarce that they don't have time to order a fridge or a laser printer. This is for the lazy guys that enjoy having an assistant because delegating makes the feel like A Real Businessman.
I bet I could follow around any startup CEO for a day and point out 50 times he's got 20 minutes to order a fridge, or whatever.
Steve Jobs or something, sure. He really could be entirely booked up every single day all day.