If you still have a large 7th gen backlog you now have to either keep two or three or more consoles hooked up if you can, or switch them any time you want to go between them. Selling your old system can also be a great way to lessen the financial blow of an expensive new piece of hardware.
Also if you didn't own the company's last gen system backwards compatibility essentially lets the console launch with an already expansive library of non-$60 titles for you to try in the seemingly inevitable dry spells of quality titles in the first most of the first year of a console's life.
AND being a college student I can't take all these systems with me. That would be expensive and it would probably also take way too much space. I use BC quite often on my WiiU and 3DS, and if the ability to play games designed for like Windows 98 on my PC counts as backwards compatibility, then I also use it there.
And maybe BC would make it so there are fewer last gen ports. -_-
BC's not necessary, particularly after a year or two to most people, but it sure as hell is convenient and a nice bonus. A system that has it would be more appealing for it, compared to one that lacks.
