I understand, for example, search with intent to buy "I want to decorate a room. Find me a drawer, a table and four chairs that can fit in this space in matching colours for less than X dollars"
But I want to do the final step to buy. In fact, I want to do the final SELECTION of stuff.
How is agent buying groceries superior to have a grocery list set as a recurring purchase? Sure an agent may help in shaping the list, but I don't see how allowing the agent to do purchases directly on your end is way more convenient, so I'm fine with taking the risk of doing something really silly.
"Hey agent, find me and compare insurance for my car for my use case. Oh, good. I'll pick insurance A and finish the purchase"
And many of the purchases that we do are probably enjoyable and we don't want really to remove ourselves from the process.