Ah, that makes sense. I only have just the media files (no metadata) stored flat in a single SSD based mount and the background autoscan seems to pick up changes/additions consistently for that snappy (especially since I only add new content but once a week or so) but if I were constantly adding things I wanted to watch on demand, used a more complicated directory structure, stored any metadata locally, had a bit more latency in the storage, or had multiple sources I'm sure that would turn into a bit of a sync mess real quick.
I also found Infuse's scanning performance to be absolute dog shit over even clean 5 GHz Wi-Fi. I solved that with a wire, but it sounds like middleware would have skipped that problem as well.