I am moving outside of my zone of expertise, but when I last looked (decades ago), systems like NSF assumed a filesystem backing store and thinks about things like byte ranges. There are a lot of operations which file systems support which work very poorly when this is not true, such as seeks, memory-mapped files, etc.

If I want the 50,004,123,121th byte of a file from a disk, that's very fast. If I want the same for a virtual object from an HTTP server, object store, virtual table, etc. it literally involves creating the whole object, and stepping through it byte-by-byte until I get there.

If the next request is doing the same 1k ahead, on a disk, that's probably in cache, and if not, I can get there quickly. If this was a SQL query, I probably need to redo the whole thing.

You get a natural explosion from O(1) to O(n) in many common cases, and for something like a complex SQL query, it can be much, much worse.