Well that I actually just take that idea as gospel/the basics at this point. In 2022 most applications should be doing things like relying on REDIS_HOST or REDIS_URL as ENV/config and using that to connect. 12factor enshrined these ideas and it's the way to go, I think.

That said, the services that I mentioned where I wanted this pattern actually already do treat their backing services this way, so the idea is more about the general idea of an code-level interface.