Learning scales for the bass guitar is a vital part of bass playing. By knowing your scales you will have a much better understanding of which note work over the different chords used in music.
Another additional benefit to knowing scales for the bass guitar is that they make great warm up and strength building exercises. Spending 5 minutes at the start of each practice running through a few different bass scales will help to get your fingers ready for playing. They can also help you to work on finger independence, which will allow your playing to become much more natural sounding and fluid.