I agree with the child comment that using different databases can hide away special database features (although ORMs unfortunately seem to be doing that anyways

I agree with the child comment that using different databases can hide away special database features (although ORMs unfortunately seem to be doing that anyways). However I completely agree with what what's really important is the different types of services you run based on the implementation. So for example when I develop my applications completely off grid, I use express + reaper to mimic S3 / cloud storage. When I deploy just swap it out with the AWS S3 service instead. I also got inspired to use this pattern when building deepstream.io, it's a node server that can take any database/cache/message bus/etc and pretty much run with it (with a small library adaptor). In that case we basically say 'the minimum requirement for functionality is XYZ and if the service provides is, we are in. Super useful.