This is not mutually exclusive. They have home made robots and let others sell robots on their website. The same way they want to use AI and have resources to make their own. One way to use is to drive those robots. Another to enhance their web site. Current version sucks. I recently return the item because their bot told it has functionality while in fact it didn't.
AWS is very much not the same as Amazon the product selling website.
The two are effectively separate businesses with a completely separate customer base.