I have no issue with using the Blue Box but the use that I would have for the switch is this:
When I am processing the bass through the modular (or even heavily through pedals) I have 2 different signal chains. Flipping the switch from Mono to Stereo would give the ability to add the second chain in an impactful way. For example, when in mono the sound is more normal, flip the switch For stereo and the second signal is going through fuzz and a pitch shifter so there is a lead sound on top of the original sound.
FYI I do also just play more normal bass but I do like to whacky too