But I guess they are talking about the "data directory" (~/Zotero on my machine) whereas the profile files that you are talking about is in a different directory (~/.zotero on my machine). Am I understanding all of this correctly?
I wouldn't particularly recommend syncing it. You wouldn't run into anything as serious as the database corruption you'd get doing this with your Zotero data directory, but you could easily run into problems, particularly if you're not careful to close Zotero on one computer before opening it on another.
In particular, there's a lock file (.parentlock) that gets created when Zotero is open, so you might be unable to open Zotero without deleting that file manually, and if you do that you may lose settings or corrupt files in the profile. Everything in the profile directory can always be deleted and recreated, but Firefox (from which the profile system is borrowed) does create that lock file for a reason.
Upgrade Storage
https://www.zotero.org/support/kb/profile_directory
My concern comes from reading this page:
https://www.zotero.org/support/sync
which suggests that syncing in this way could cause data loss.
But I guess they are talking about the "data directory" (~/Zotero on my machine) whereas the profile files that you are talking about is in a different directory (~/.zotero on my machine). Am I understanding all of this correctly?
In particular, there's a lock file (.parentlock) that gets created when Zotero is open, so you might be unable to open Zotero without deleting that file manually, and if you do that you may lose settings or corrupt files in the profile. Everything in the profile directory can always be deleted and recreated, but Firefox (from which the profile system is borrowed) does create that lock file for a reason.