SB - mainly for stability, the 60' boat that I normally sail is certified to self-right from 168 deg of roll when carrying a full main and head sail...takes a lot of righting moment to drag that much sail through the water!
I'm not a fan of swinging keels, we use water ballast - we can add 8 ton of weight to the right bits of the boat when we need it, and get rid of it when we don't.