It may not have necessarily been the bass player's choice to play that particular fill. Sometimes, that comes from the producer or someone else with a bigger say over how the song is played. It also could've been a "hey, just try doing a descending C scale here" and it ends up getting "comped" into the final mix.
I always think of the story about the "Pat Boone/Debbie Boone" drum fills all over the Guns N Roses "Use Your Illusion" albums (think "November Rain"). Matt Sorum has taken a lot of crap for that, but he played that fill so often because that was what Axl wanted.
