I think there's a difference between a typical website chat window and how many people would use ChatGPT. The latter has tables, images and links which is enough to build up comparisons, order sheets and then ultimately have a format for confirming a purchase. I use it a lot for doing basic home construction comparisons (materials, volumes, etc) and could definitely see it getting to the point that it organised an order for me to submit, and eventually to where the submission and payment were within the chat.
A voice assistant doesn't give you that option to review, but maybe it'd work for ordering fast food. A small chat window could grow to work for simple purchases like takeaway food or small hardware, etc.
I am not so sure about that. The modern web has become complicated/unusable enough that I can see a lot of people prefering a chat interface over having to click through this unholy mess. I might be biased, as I have to deal with accessibility ussues on a daily basis. However, there is a whole demographic we're currently leaving behind. There are a lot of people around who simply don't try to use the Internet to get things done, because they are overwhelmed with how it works. My mother doesnt even want to click on a YouTube link sent to her via WhatsApp, because she would leave the well-known app and have to deal with the web... However, I can imagine her using an agentic interface to get things done, although not right now, maybe in 2 years.