We stored lots more than just "notecard entries" in the Newton object store. We had application packages (with demand paging of compressed code). We had "large binary" support, similarly demand-paged. And all of this stuff was hooked up to the garbage collector.

I don't know how well it would scale to a non-hand-held device, but it worked really well on the Newton.

Files are useful, but they are not necessary. We are used to them, but there can be better ways to do things.