TBH I am surprised how many people are saying $0 considering PS4/ONE games jumped $10 or $20 (in some regions) at launch during the launch period compared to their PS3/360 counterparts. There was some complaints but overall majority was happy to pay it which I found odd considering that most were not technically better other than some rending and a bump in resolution. i.e. not like the game was remade considering their was a PC version to use assets from.
Surely portability and the use of a more stable medium (i.e. won't scratch or break in half as easily) is worth an extra $5?