Would you actually use three amp blocks in a preset if there were three blocks available?
1++On the III, with the multiplexer block, it would be a great way to switch between clean, dirty & lead gain quickly with no dropouts at all, assuming there are no dropouts caused by other blocks switching channels.
The instant advantage of this for my pro clients would be that you get one for clean, one for rhythm, and one for lead without changing channels or presets. This is the ultimate power trio.