What is the benefit of using the opposite or "reverse" sideband when receiving CW?
Why A CW receiver produces an audio tone by mixing the incoming signal against a BFO, and that tone can come from a signal either above or below the BFO frequency. Switching to the opposite sideband keeps your desired signal at the same audio pitch but flips the RF image of everything else, so an interfering carrier that was landing inside your filter may now fall outside it. This is a quick way to dodge QRM without retuning or moving frequency.
Watch out The idea that it lets more stations fit in a passband confuses this with narrow filters or changing bandwidth; reverse sideband does not change the receiver's bandwidth at all, only which side of the BFO the RF is taken from. Impulse noise is broadband and is unaffected by sideband choice.
Reverse CW sideband = flip the interference to the other side of your tone, your signal stays put.