Sftp is useful, but is pretty slow, only good for small amounts and small number of files. (Or maybe i don't know how to cook it properly.)
WebDAV shares of the NFS shares for things that need that view
sshfs for when I need a quick and dirty solution where performance and reliability don't matter
9p for file system sharing via VMs
Google Drive. Or Dropbox, OneDrive, yada yada. I mean, sure, that's not the question you were asking. But for casual per-user storage and sharing of "file" data in the sense we've understood it since the 1980's, cloud services have killed local storage cold dead. It's been buried for years, except in weird enclaves like HN.
The other sense of "casual filesystem mounting" even within our enclave is covered well already by fuse/sshfs at the top level, or 9P for more deeply integrated things like mounting stuff into a VM.
No one wants to serve files on a network anymore.
I'm tinkering on a project where I'd like to project a filesystem from code and added web-dav support, the 50mb limit will be fine since it's a corner-case for files to be bigger but it did put a dent into my enthusiasm since I had envisioned using it in more places.
Nothing for multi-user or multi-client. Avoid as long as that is possible since there is no good solution in sight.