Yes, the technical vs legal angle wrt to electronic communications is different.
If I understand it correctly, The electronic system for allowing access to systems doesn't suffice for legal purposes. The electronic system can be as tight as possible, but you have to be able to prove legally that the person gaining access to a system with proper electronic credentials is the actual person who was granted those credentials.
P A I, then is one person with a unique personal password signing in to a secure system.
The non-repudiation part is that the person who gained access has to be able to prove it was actually them to another party with such evidence that the second party can convey that same corroborating evidence clearly to further parties.
Say a person is accused of a crime and uses the excuse that they couldn't have been at the scene of the crime because they logged into to their email account from their home computer during the time in question. There has to be a system in place that proves it was the person himself who logged in at that computer for it to hold water legally. i.e. not hearsay or testimony by his wife, etc, rather bullet proof biometric evidence.