Probably a minority thing nowadays, affecting only old-fashioned people such as myself, who enjoy sending postcards per snail-mail; especially from places to which I go on holiday (although postcards in great quantity and variety, are still made and ubiquitously on sale). I would ban the practice which too many postcard manufacturers engage in: of making the "blank" -- for message and address -- side of the card, with a slightly "laminated", over-smooth-and-glossy, surface; parts of which will often refuse to take writing in biro. One thus has to switch, "midstream", to some other kind of writing implement -- more than a little annoying, plus it tends to give what one has written, a slightly grotesque appearance. A prominent offender here, is the Isle of Wight-based firm of Nigh: specialising in cards (excellent in range, and picture / theme quailty) of I.O.W. scenes.