Yes but now you also have a network to maintain.
> Just start with Postgres or MySQL in the first place. It's just as performant, just as easy to set up
Yes it's easy to set up. But then you have to maintain it. It's another daemon that needs care.
And you don't have to do any more maintenance on Postgres/MySQL than you have to do on SQLite. You can leave them running for years without touching them. Maybe you want to upgrade them, but maybe you want to upgrade SQLite too.
Well, I'm sure the db server has an IP address? Is it IPV4 or IPV6? How do you receive the IP address? Can it change or not? How do you secure the connection between your web server and the database? Should the database only accept network traffic from your web server or from the wide internet? If the former, you have to keep that in mind when adding a new web server. If the latter, make damn sure the credentials don't leak!
Congratulations, you now maintain a network!
I call it five minutes of setup, if even.
And if you're dealing with SQLite, are you making backups somewhere on a network? Securely? With credentials? Where do you keep the credentials for your webserver itself? If you're running a website, you're dealing with a network and credentials from the start.
Compare that to the days or even weeks it's going to take you to migrate to a client-server database platform as soon as you need to scale to two webservers. All the queries that need to be tested and modified as necessary... potentially different table structures... the migration of data... no thanks.
But I guess this all depends on whether it's B2B (likely not to have that many customers), B2C (potentially more users), or a hobby project (gimme operational simplicity!). And many other variables. YMMV!
No it's not. Network latency is negligible, assuming your database isn't halfway across the world or something.
And as soon as you have to scale to just two webservers, you've either got to implement a client-server network layer on top anyways, or else the complexity of a replication layer.
Just start with Postgres or MySQL in the first place. It's just as performant, just as easy to set up, and can actually scale as you need it. Don't be "brave" when there isn't even any payoff involved.