Good deal for the customer, not the person who traded them in 
Of course. I shit you not, Game wanted to give me one quid for about 10 XBOX 360 titles, all of which were relatively new (3-5 years old). But then again, I hardly ever trade in games, so I don't really care.
Don't you mean not for the game developers/manufacturers and good for the customers? Seeing as games developers don't make any money from sales of pre-owned titles, which is why companies are putting stocking prices up to deter this, along with the rumours that the next generation of consoles may include a "one console per game" lock system
This was one of the main reasons for the whole GAME/EA controversy. If you go into the store and ask for a title, and they have it pre-owned, they will encourage you to take that copy instead of paying the full retail price for a brand new copy, which in turn was losing EA serious money.
I can't stand EA to be quite honest with all the bullshit that surrounds them such as the decision to realse day 1 DLC, but I guess business is business.