You can access files that contain certificate information (on any OS), but you can't access individual certificates as their own object. In your output, you're listing files that may or may not contain valid certificate information.

The difference is similar to being able to do 'ls /usr/bin/ls' vs 'ls /proc/12345/...' , the first is a literal file listing, the second is a way to access/manipulate the ls process (supposedly pid 12345). In windows, certificates are not just files but parsed/processed/validated usage specific objects. The same applies on Linux but it is up to openssl, gnutls,etc... to make sense of that information. If openssl/gnutls had a VFS mount for their view of the certificates on the system (and GPG!!) that would be similar to cert:\ in powershell.