As the post explains, the Reliable and Safe bit are really handled by the car, not the charger. This is a neat project, but it is also another example of an Arduino being a bit overkill for what is going on here.
As you said, the car side is dealt with by the car itself. There are some minor issues (read the YouTube comments, people on YouTube love to comment about safety, justified or not!) but overall quite reasonable from a safety perspective.
This is a slow charger and that car is not that different from a regular appliance from the charger point of view.
Edit: my buddy is ex-googler. IQ is twice his weight. I wouldn’t trust him any electrical cable. He can work on ground breaking theories, but breaks everything what he touches with his hands.
Certain professionals should be licensed, because people need to know they are safe, but within your personal domain you should have a lot more freedom.
Because shit causes fires and burns my house down. That’s not to say it can’t be done safely, and if you’ve got the space to do it away from other people, such that the only person you hurt is yourself, then by all means I think you should be able to do your thing. But codes should come into play when it's being done in a garage attached to a home where the partner, kids, and dog live. if I blow myself up, that's totally on me. taking other people with me isn't okay.
Not all of it; the whole point of having a controller on the wall box is that there's mains power in the cable only while it's plugged into a vehicle (and that this power is removed immediately if the cable is pulled out from the vehicle, which could help prevent arcing on the contacts if it happens while charging).
That is completely wrong.
The EVSE is responsible for implementing a GFCI cutoff as well as an over-current cutoff. Those are both safety features. A failure in the car's insulation resulting in a short to the frame is a shock hazard. A shock hazard also exists if the charge cord insulation is damaged. A bug in the car's charger firmware that results in too much current draw is a fire hazard.
Additionally, the EVSE must keep the contactor open unless the plug is attached to the car (sensed via the [edit: pilot, not proximity] pin). Again, a safety feature because the J1772 plug is large enough for a finger to accidentally contact the conductors.
Yet another is that the EVSE informs the car of the maximum safe current via a PWM signal. Too much current = fire.
The car can't help you with any of those safety aspects.