Sidebar: I love how Amazon basically gave up on AWS Chime for Slack. Even dogfooding their own messaging product didn't work.
All the "we built it so we could say we have it in sales meetings" stuff is pretty bad
For UI though? I mainly use the shopping site, AWS, and Prime Video, but none of those are productivity-style apps, which need to have less basic workflows to be competitive. Can you name any successful Amazon apps along those lines?