What you're missing is complexity and second order effects.
Making decisions about databases early results in needing to make a lot of secondary decisions about all sorts of things far earlier than you would if you just left it all in sqlite on one VM.
It's not for everyone. People have varying levels of experience and needs. I'll almost always setup a MySQL db but I'd be lying if I said it never resulted in navel gazing and premature db/application design I didn't need.