Among postcard collectors who specialize in social history, the genre of card you see here is known as a “walker.” “Walkers” are comparatively rare and frequently are real-photo cards.
Leather postcards? Are they a contradiction of terms or are they collectibles because of their unique quality? A casual observation suggests there are few collectors, but those who are dedicated to leather cards are eager to talk about their collections. Some of them try hard to get others to join them.