100 postcards in a box

Gabriel Campanario's hugely successful book The Art of Urban Sketching was published in 2012, and I was lucky enough to have my drawings included in it. Now comes a boxed set of 100 postcards of different images from the book – again including something by me – on sale in the UK from 2 April 2015 (Quarry, £12.99), and already out in the US. It's a great collection of scenes from every continent and 30 countries drawn on location by many of my favourite urban sketchers.
It's a tricky one: are they too good to post to people, or so good that they shouldn't be kept in a box but shared through the post?