I prefer to have different basses with different personalities. I don't have the need to have only one bass to every musical situation. To me, it's more fun to look to all my basses and choose one depending on the mission (Just like the assembly of a Mission Impossible squad).
Besides that, to play different basses make me a different musician as well because its ergonomics put me on different frames of mind (something that only one bass can't do to me). I like that.
I like having more than one bass and more than one sound. Maybe I should have said that I want is to be able to use my fretless in any setting. I want to get used to hearing that sound any time I play bass even if I choose not to use it.