To do readings on your cell phone with. I don't like to carry around a deck, but i do do readings via my cell during the day if I feel the need for advice.
I used to have the Tarot of the Divine, but my phone myteriously reset itself and I lost it. I now have The Touchstone and Psychic Tarots on my IPhone...and a few assorted angel decks.
I also have about 30 Orphalese decks on my computer, but that may be getting off topic.
Babs