Certificate keys aren't used for encryption anymore anyway.

A modern TLS connection uses an ephemeral key-exchange protocol where both parties opaquely agree to a one-time-use random encryption key that is not knowable to any other party, not even someone who can gain access to either party's private key. This is called Forward Secrecy (originally and sometimes still known as Perfect Forward Secrecy or PFS, but the use of the word "perfect" in any cryptographic context is akin to naming a ship "Unsinkable").

Right, thanks for correcting me. This stuff is not so simple to get right.