Metaphors are part of visual communication. Blatantly disregarding metaphors creates unnecessary confusion and abstraction--it separates the interface from culture.

Remember, all of this stuff is ultimately (and most truthfully) 1's and 0's. There is always abstraction. It is best to choose the abstraction that is most DESCRIPTIVE.

I did notice that the proposed "Purely Digital" interface included icons representing an old style phone handle (which younger customers probably haven't seen), a physical letter (increasingly rare), and a paper wall calendar.