I learned how to read music whilst I was in school when I played cello and piano. I can't sight read and play along too well on a bass...not as well as a piano, but I can look at the notes and tell what I need to play and in which key. The only time I read music is when I play Jazz or discuss bass melodies with a keys player. I play mostly by ear, but if I am stuck for ideas I usually refer to the sheet music. It's certainly very helpful to know.
The benefit that you get with learning how to read music is that you can pick out the pace and the beat of the melody and rhythm much better than tablature. Reading music is really not that hard...I would say it's easier than learning tablature. I think a lot of people are frightened to learn. You will get to know your fretboard, notes and scales much better reading music. Tab tells you where to place your fingers...sheet notation tells you what notes to play and you must know where on the fingerboard to play the notes. There's quite a difference. It's a bit more challenging, but it's definately worth learning and it improves your scale knowledge.
