Don't hard links suffer from the issue that because they're actually links to a specific file, not path pointers, that you can replace the target file thinking you have updated something in the system and instead have stale hard links lying around, referencing the older version when you intended to replace the older version for all users?

I think that in a hypothetical world where symlinks worked like hard links, we'd be swapping out the security complaints in this post for articles about how hard it is to upgrade a POSIX system properly, tools and tricks you can use to make sure you truly replaced all instances of a binary with a known vulnerability, and so on.