Still have to wonder how in the world they were invited to the Big Ten. Pitt would have been better and not kidding.
As has been pointed out, they were mainly brought in for BTN TV revenue as it made New Jersey and kinda NYC as "in state" so it added money to the coffers of the league. Also, Rutgers was willing to take a one sided deal to join with smaller payments for an extended period of time (but still more than they were getting from the Big East at the time) which increased the pot for everyone else to share. Also, Rutgers was viewed as similar to other Big Ten schools as a large land grand flagship institution.
Also, worth noting that Rutgers was really only considered and brought on because the Big Ten wanted Maryland. UMD is the team they pursued in the cycle as they actually did have value - have some decent sports and actual fans, new state (so BTN TV argument like Rutgers) but also brought the conference into the DC area. That presence was viewed as very important in terms of having access to federal research money so the schools wanted to have even stronger ties the region. Once UMD was brought in, they needed another school to keep the conference at an even number and Rutgers was chosen.
That being said, IMHO they should have grabbed Syracuse instead of Rutgers and thought so at the time. Syracuse would have been a better fit culturally/geographically despite being private and actually has better athletics. Plus just a crapload of people in the media.