Bass guitar slides are an important part of bass technique. Whether you play one to enter a verse or you use them in solos, fills, or bass lines, you'll want to make sure you have the technique locked in.
Slides form part of articulations. Others include hammer-ons, pull-offs, bends, vibrato, and ghost notes. They really bring flair to bass playing. Here's a video that goes through how to play and use them.
For more technique exercises, check out my book Creative Bass Technique Exercises.
By the way, for a brilliant example of slides in a bass line, here's Flea's on Purple Stain by Red Hot Chili Peppers.