Battery disconnect on both negative and positive?

[tonyg]

Hello,
I've got Blue Sea battery disconnects, two, one red, one black.

Any reasons why not to have both in my system on the battery wires?

 

[rmaddy]

Since you don't need a switch on both wires then adding a needless switch adds unneeded complexity, unneeded resistance, unneeded opportunities for bad connections/crimps, and extra cost.

 

[tonyg]

I saw systems were they had disconnects on both wires, wondering why then?
Is it possible that some batteries need both sides disconnected - i.e.: pylontech?