From Dictionary.com...
phi-lat-e-ly [fi-lat-l-ee] –noun
1. the collecting of stamps and other postal matter as a hobby or an investment.
2. the study of postage stamps, revenue stamps, stamped envelopes, postmarks, postal cards, covers, and similar material relating to postal or fiscal history.
From this definition, I would say, yes! All mail is philatelic, but only to those that collect or study it. To the lay person, I would think not.
Steve

