GEP,
I agree that it is the responsibility of the PIC to carry charts, and if he/she relies on an electronic chart, that includes a suitable back-up since losing the chart in the middle of the flight is not acceptable.
But where do you take it from that the chart must be in paper form? How does the ANO imply this - perhaps in another section?
And if it relies on the interpretation of the word chart, is there any precedent?