Late response that no one mentioned: they don't rock in side waves as much and not at all when under speed, nor pound when going up wind. That is one cruising advantage they have to counter the less space. You can comfortably write or cook in most conditions.

The lower main hull space is not actually too terrible, either, since you can store some things in the amas like your beacons, folding bike, inflatables, etc. and keep day to day items in the main hull.

Another advantage is more solar space that's also less likely to be in the sail's shadow.

They're better than a catamaran in every way except for space.