SQLite is almost perfect for a small local application. There is no database server to configure, the whole database can live in one file and development is incredibly simple. Then you deploy the app to Vercel. The application may still build successfully, the database file may even exist during deployment, and everything can look fine at first.
A web app can work perfectly on localhost and still be nowhere near ready for another person to use. Locally, a lot of things are conveniently invisible. The frontend knows where the backend is because both are running on my machine.
After putting a small site on Firebase Hosting, I immediately ran into the next problem: the default web.app address worked, but it did not feel like a real home for the project. I wanted my own domain. Before doing this myself, domain configuration always sounded more complicated than it actually is.
I needed a very small public website for an app: some legal pages, a basic landing page and an app-ads.txt file at the root of the domain. This is exactly the kind of task where setting up a traditional server feels ridiculous. I was already using Firebase, so Firebase Hosting turned out to be a very simple solution.