I can see a lot of benefits of having 1 API to access a lot of functionality.

For example instead of integrating with a message queue I can just do an INSERT this is great. It lowers the friction.

Vector search is a no brainer too. Why would I have 2 databases when 1 can do it all.

Using Postgres to generate HTML is questionable though. I haven't tried it but I can't image its a viable way to create user interfaces.