No, their contribution to algae control is minimal. Many don't eat any at all. And most tangs like 6' + tanks to be happy.
Would disagree with that, they are naturally algae grazers in the wild. My tangs are constantly picking at algae on rocks all day.
Tangs are nothing but poop machines
as much as I love tangs, I won't have one in my tank. too much fear of ich. my one spot foxface does the job and is a much hardier fish.
Depends on the tang, but I wouldn't consider them to be part of cuc either way.