No lie, on every bass I have owned, the open A string is one of the best tones the bass made. (Some Fenders might ruin this, unfortunately; mine is fine.) Something about the timbre of an open A is just right. Perfect timbre IMO.
Some basslines, and especially pedalling or chugging ones, work much better with open strings.
Hysteria is an interesting example. It might even be easier to play by fretting notes, but simply works and sounds better working with the open A and E (and working down the A string for Am rather than staying in the box.) That’s also how Wolstenholme plays it.