Ratch:
Clearly the Coulomb is not a unit of energy. I didn't catch that. Britanica is clearly wrong.
In any event the charge on an electron is the smallest amount of quantized charge that can be transferred. And electrons don't really flow, they basically colllide within the material, so it's not the same electron that started the journey as the one that finishes it. Hole and electron flow have historically been used to describe semiconductors.
Way back when, I learned that electrons are in circular orbits. Later I learned that they are in essentially probablility functions as to the position around the neucleus of an atom.
One day you learn that paper is an insulator and the next your measuring the resistance of a piece of paper.
Another day, you learn that waving a wire around in the air generates a voltage. It's a wire in the earth's magnetic field, so it does generate a voltage based on the fundamental concepts and can be measured.
Flexing a shieleded cable also generates a current and there are special graphite impregnated cables that lessen these effects.
Squishing an insulator also generates a current.
Two different metals at different temperatures, e.g. solder generates an offset voltage.
Most people don't have to take these effects into account and most people probably have never seen an instrument that can measure the phonomena.