You're right, 5C Nano does have touch. My error. The real difference is behavioral: Nano's flush design trains you to leave it plugged in permanently. Attacker with brief physical access can touch it ...
Yes, that's true. I try not to forget to take my Yubikey in my pocket when I'm in a public place and have to leave my laptop unattended for a few moments, but I must admit that I tend to leave it connected at all times.
However, I always lock the session.
However, I always lock the session.