I'm probably overlooking something, but what makes the problem of being able to get from item in basket to item is shipping different from choosing which item(s) to put in the basket?
In other words, if Agents are able to navigate marketplaces, shouldn't that imply they can also navigate a subset of the marketplace, the payment section? Especially given that that section is "easier: theres no need for qualitative (or quantitative) judgement like there is for the shopping portion.
It would/will be extremely irresponsible to put non-deterministic and fallible models in charge of weapons. We are not close to having solved the problem of ensuring AI pursues good outcomes