I'm not sure what the original commenter meant; however TLS is useful only when talking with your own server. What about other connections? NTP, DNS etc are all unencrypted (read: unsigned). Google "DNS client CVE" for instance. Or what about SSH? It may not be accessible from the Internet, but still exploitable from an infected host in the LAN. Someone has to keep all that software updated. In those conditions, I would never connect a RaspberryPI or similar to my door / gate / car / ...