The ultimate problem is the incentives. Web stores are already forcing us to use their proprietary (web)apps, where they define all of the software's capabilities.

For example, subscription purchases could be a great thing if they were at a predictable trustable price, or paused/canceled themselves if the price has gone up. But look at the way Amazon has implemented them: you can buy it once at the competitive price, but then there is a good chance the listing will have been jacked up after a few months goes by. This is obviously set up to benefit Amazon at the expense of the user. And then Amazon leans into the dynamic even harder by constantly playing games with their prices.

Working in the interest of the user would mean the repeating purchase was made by software that compared prices across many stores, analyzed all the quantity break / sale games, and then purchased the best option. That is obviously a pipe dream, even with the talk of "agentic" "AI". Not because of any technical reason, but because it is in the stores' interest to computationally disenfranchise us by making us use their proprietary (web)apps - instead of an effortless comparison across 12 different vendors, we're left spending lots of valuable human effort on a mere few and consider that enough diligence.

So yes, there is no doubt the quiet part is that these "agents" will mostly not be representing the user, but rather representing the retailers to drive more sales. Especially non-diligent high-margin sales.