> an in-process method invoke.

Pedantically it's an in process virtual machine for operating on structured data. Which is precisely where it shows it's weakness, in my experience, when you end up with complicated table structures and complex join mechanics you then need to start thinking ahead of the query planner and VM code a bit in order to maintain reasonable performance.

There are more than a few unusual things worth knowing:

https://sqlite.org/optoverview.html