>There are two downsides of mmap - I/O errors can't be caught and handled by SQLite code,

True. https://www.sqlite.org/mmap.html lists 3 other issues as well.

> and buggy stray writes by other code in the process could corrupt the database.

Not true: "SQLite uses a read-only memory map to prevent stray pointers in the application from overwriting and corrupting the database file."