I agree with that for most tones. I find it useless for clean tones as well as most high gain. Where I think dual amp tones can shine is in the light crunch/edge of breakup area. Fractal has a factory patch of multiple scenes of Vox and Plexi amps together, and it just smokes. I really can hear the dual chime/kerrang characteristics playing well off each other, and it's inspiring for songwriting.
Aside from that, you're probably better off with a single really good amp model/capture, but going out to dual cabs with different, but complimentary properties.