I own Dead Rising 3 on disc and rebought it just to have it digital. Same for State Of Decay, bought it for $6 at Target clearanced but picked it up digital. Looks like it's trades in for $11 at Gamestop, so not bad.
That's the digital double dip, or 3D.
For something like Resident Evil 4, if you had it for Gamecube / PS2 / Wii, 3D'ed it last gen, then bought it digitally again this gen, you'll have to get a table.