Nice advice, there's a lot of variation on the role. And yet, some things seem to always be there.

Clearly not a style which works for any and every applications. Still, it's definitely a good thing to aim towards such an architecture. It brings really nice properties in terms of testability and safety.

Interesting point. As we see the collapse of public forums due to the usage of AI chatbots, we're in fact witnessing a large enclosure movement. And it'll reinforce itself as the vendors are training on the chat sessions. What used to be in public will be hidden.