I am by no means saying that Dragon Age: Inquisition is not worthy of such a feat but there are some forms of “cross-buy functionality” that would increasingly improve the digital stores of the newest generation of game systems. One time in particular I found that the PSN card that I have redeemed on the PSN network on my PS4 did not cross over to the same account on my PS3. I have also heard similar stories on instances like this from my friends with the Xbox One and Xbox 360. The fact that DLC can be officially deemed as cross-buy compatible, files that are likely much more complex and difficult to code than the simpler concept of online credit seems a little odd to me.
However the sign that DLC is able to become “cross-buy” might mean that it might be a stepping-stone toward more games becoming cross compatible among the eight and seventh generation consoles. It seems only time will tell to see what possibilities of cross-compatibilities can become reality.