Main reason is that SQLite is embedded with my application. There isn't a second, third or fourth "microservice" to spin up. I know Terraform/Docker, love them, but the gymnastics I need to orchestrate for my particular situation is not worth it.
So for the tradeoff of complexity for functionality, SQLite hits a very good sweet spot for me.
What are the advantages, in your own experience, of using SQLite instead of something like PostgreSQL? With PostgreSQL, you could run database migrations during business hours and use a proper ALTER TABLE.