> an in-memory “database” that gets backed up to a file is perfectly reasonable.

We have org-mode, application configs, and music playlists as three widely used examples for this.

You switch to a database when you need to query and update specific subsets of the data, and there's the whole concurrency things when you have multiple applications.

There's absolutely no problem with this. But it probably shouldn't be a best practice or default for the industry? That's what op was saying. I'd argue you're still better off using SQLite than doing it manually, but to each its own.