Plenty of my friends like to trade games in for store credit, and essentially buy new ones with that credit. That won't be possible anymore, and the shops' business will suffer for it. You may not care, but it's Microsoft who'll be reaping what would have been their profits. Does no one see this as a bit too greedy?
Have you ever been to Gamestop? Have you ever tried to buy a new game, only to have them try to push a "like new used game for $5 less" off on you? Gamestop does this because their profit margin on it is huge.
And do you know how much money the developer makes on each used sale? Zilch. Used games are exactly the same thing as piracy when it comes to developers making money.
Gamestop has for years been deliberately harming new sales by aggressively pushing used. Whereas the developer makes more money when there are no used games, who makes money on used games? Just Gamestop, which is a parasite that contributes nothing useful.
Meanwhile, on pc, you have Steam. Steam games are cheaper than console games and new games regularly go on firehouse sales. I've picked up six month old titles for $20 on Steam. You will never see that on consoles ATM, and that is specifically because of the used market.
This new system is much better for developers and it will be better for people who actually buy a lot of new games. It will be worse for people who mostly buy used games, but they may as well just go pirate their games anyway, for all they contribute to the useful parts of the industry. The only group that truly suffers here is Gamestop.