Short answer: ease of use. Setting up shared folders cross-platform is non-trivial for the average person.

The long answer is that transfers and shared storage are fundamentally different use-cases (imo). Shared storage usually means you grant and revoke access to a subdir (ACLs), which are (1) often overly permissive and (2) exposes a file structure that isn't necessary for the other side.

Transfers OTOH is an ephemeral action where sender picks files from their file system, receiver decides the destination directory (so file systems are not exposed in either direction).

That said, if you are looking for shared storage, check out https://www.spacedrive.com/. It's also built with Tauri.

> Setting up shared folders cross-platform is non-trivial for the average person

It's nontrivial for me either. Until Windows got a native SSH client, it was the same problem every time: do I install like an FTP server somewhere and use Explorer, or set up a samba server on my linux box or how even do I copy more than a few megabytes... I don't understand how normal people can do this if even I have trouble, especially between two different OSes. Probably usb sticks are the answer, but then normal people don't have micro-to-female-A converters to connect flash drives to a smartphone, or know that you can even do such a thing.

And so that's why I maintain https://dro.pm and, e.g. when implementing encryption (which I didn't end up implementing because it was literally impossible given the ~2020 state of browser support), one of the main requirements is compatibility. If it's not going to work on any potato, I might as well not have it half the time, because on my own hardware I can usually just ssh. Unless you really want to transfer more than a few gigabytes of data, this works reliably (good old 90s <input type=file>, no JavaScript magic in that part) and the occasional wait is better than having to do sorcery with custom software on both ends, also because I usually don't own the non-linux endpoint.

Device to device (PCs, tablets, phones) file sharing within the Apple ecosystem is relatively easy, even with strangers if you set your airdrop to ‘everyone’.

I’m not aware of a Windows version of this that “just works”. SMB has a lot of weird error edge cases, especially when firewalls are involved. I’ve used the Win10+ OpenSSH service to transfer files a number of times, myself.