The blockchain is already 15 GiB. Bitcoin can't replace credit cards if we don't solve this problem.
What are you, living in 1995?
15 GB is not large. Any one of my 60 games on Steam are that size or bigger.
But it was about 2GB a year ago. At this rate, it will require a NAS with several dozen 4TB hard drives in RAID by the end of 2016.