How many files do you have? At what scale did you see this being a problem?
I'm a fan of Obsidian, not affiliated with them, but my experience with basic file syncing like syncthing or git is that you should be able to easily get up into the ten's of thousands of files without an issue.
The Obsidian Sync (official) plugin isn't very clever with its syncing, it does one file at a time, seemingly new requests for each file.
I recently had to sync a new Obsidian vault from scratch, a vault with thousands of files, and it took minutes to complete because of this, even though most files are a couple of KB at most.
Easy to fix and low hanging fruit, but still an issue for us with many files in our vaults.
Same here, but the problem is bigger than that. Having to manage a ton of tiny files makes it easier to lose tiny bits of data. What happens if a file changes, gets overwritten and you don't notice? It's much easier to 'version' a single larger file than many hundreds (thousands?) of tiny files containing 4-5 lines at most.
I don't need entire files for each individual book/movie/task I want to manage.
They'll have maybe 4-5 properties at most with not much content in them.
File system, and syncing operations will take a massive hit if I have to manage that many files.