It's a bit reversed, labor unions are cooperatives, not the other way around, as cooperatives are more flexible in arrangement than unions.
Don't disagree with the rest of the comment though.
EDIT: also, I wouldn't consider coops an anarchist victory over traditional private companies anymore than democracy over monarchy. The corporation > worker hierarchy is still there, even with the different share distribution. It's a good demonstration of an alternative and underappreciated corporate structure, tho.
If that were self evident how come there has never been a company that started with employees unionized? To get this supposed benefit