Single sideband (SSB) advantage is that it is a more efficient type of communications vs straight amplitude modulation (AM) that is used with a radio w/o SSB. Think of the upper/lower channels as only having to use 1/2 of the signal of the regular channel. Power, band width and signal to noise (SNR) are all improved. That equals more effective and reliable communications. ( SSB was the method for a long time btw NORAD and our Nuke bombers)

All that said, as CB's have been slowly being replaced by other communications devices, I'm guessing mostly serious CB'rs are using the more expensive SSB radios anymore. I have one (SSB) but its to big for me to mount in my Commander so I'm using a Cobra 75 WX ST Remote Mount. Not SSB but it has other help,,, and I have other comm. installed and more to finish whenever I can get time.

There is much more to SSB,( and most of it I don't fully understand), but hope that helps..