It's probably the largest in-use uri scheme they have dropped. At the very least, there should be better error handling. For me on Chrome/Windows, ftp:// uris just don't do anything[1]. No error, they are just inoperable links. Yes, I could fix that, but for average users, that part of whatever you want to call it could just disappear silently.

[1] Because the default handler for ftp:// was originally Chrome on my system, which is pretty common. Chrome dropping it didn't change that mapping.