It's advertising for the new trade paperbacks.
You're not going to buy the back issues, because you're comfortable with the decisions which you have made, so you're not going to buy the trades either, but if you get sucked into this Zero issue bullshit cross over, suddenly you're forced... TRICKED into liking something new and you are buying BOTH the trades and the back issues.
The zero issues.
Either sell them for 25 cents each or spray the internet with free digital copies.
There's no such thing as a free lunch.