I travel a lot, and I like to take my games with me, so it's much easier to take just a system with games installed to it / downloadable, than it is to haul the system and individual games, this is why handheld gaming works for physical cards, you can buy those little pouches that hold 50+ carts in a very small box that you can take with you, trying to do the same with standard console games with optical media is just a headache because they either take up way too much room or are way to easy to damage.
But then, I can download/install a modern 40gb+ game in minutes where I live so it makes more sense for me to go digital, if i was living in the sticks in the UK/EU/US and surviving on poor speed dialup/adsl, Digital is the last thing I would do.