Sanders dragged the Lions to what was at that time their only NFC championship game appearance ever in 1991, with a backup QB starting all but the first couple of games that season and Wayne Fontes at HC.
It was the terrible owners and management that made Detroit bad for decades, but Sanders was so good in his prime that he made them a contender for a brief window, as a RB.
The NFL values RBs differently now, but if you have a chance to draft a guy (even at RB) that is most likely to be the best player on field every week, you do it.