Have to account for initial cost of the game and PS Plus combined, so yea if you exceed that somehow with magical business powers.

Riddle me this. How the fuck is he making money? He bought the game physical I'm assuming perhaps 60 dollars brand new. He then buys the digital copy for 5 dollars. So he has spent 65 dollars on the game and then trades in physical for 20. He still has spent 45 dollars on the game. If you count that as making money then you need to go back to economics 101.

You aren't a true video game collector then.  Physical is always better than digital except perhaps with Steam on PC and indie small games on home/hand held.  Good luck selling that digital copy in future.  People can still plug in carts from 20-40+ years ago and they still work.  What are you going to do to try and make money of that digital sale in future?  Sell your whole account which they probably don't allow if caught.

Doing it all the time on Xbox.
However "making" money isn't the right term. More like make some of the money back.

The price of Just Cause 3 will quickly go down by a lot. Making a profit is nearly impossible at this point and honestly it's probably not worth the hassle.
I still have the retail versions of Sunset Overdrive and Project CARS for example and they are not worth more than 5€ at this point.

Lol true video game collector.  I'm a gamer not a collector. 

I was just giving you a hard time.  I'm just one of those stuck up physical > digital guys even though I have a large Steam collection and eshop games on my 3DS/Wii U.  I still just prefer physical over digital because eventually it increases in value while owning a digital copy doesn't really translate to any value.  I can see the ease of use being top reason to get digital though.  So basically physical and digital have both positives and negatives attached to them.