Lots of senior executives, celebrities, etc have other people buy stuff for them all the time - flights, gifts, lunch, etc. The problem is this is very expensive so not available to most people. If agents reduce the cost and are mostly reliable, there will be a significantly large market for this service.

I agree. I'm confused that this idea is even controversial. I would absolutely use it in the way you're describing. I've wanted something like this since around when Alexa/Echo launched.

There is a 100% chance that companies paying a fee to the owner of the agent will be picked by the agents.