I would say, maybe not switch over if you need something that has been rock-solid for years and years.
If you want a shit-ton of built-in features DuckDB is pretty damn fast even with non-column store optimized queries. Surprisingly so! I have done side-by-side tests and you really have to have a lot of rows for it to start to make a difference. And their built-in functions are awesome. And they (company/group) are awesome and very responsive!
Having said that DuckDB is still young enough to make me nervous putting in critical application stacks and I feel about Sqlite the same way I feel about PostgreSQL ... it is solid as hell and will just work.
I will say that I have not had any stability issues in any of my personal projects that I use DuckDB in, it is just that I know for a fact that Sqlite is solid.
one thing to be aware of is that duckdb doesn't currently allow concurrent readers and writers (unlike sqlite). depending on your use case, that might be a showstopper.