I see the workplace benefits of a global union (specifically the IWW) as a bonus, with the real meat being that it teaches people how to organize, and how much power they truly can wield if done together, as many people still feel quite powerless despite the potential they hold, they need only be taught how to use it.

When the Spanish Civil War kicked off, it was the Syndicalist unions (CNT-FAI) that were able to organize their communities effectively to resist Franco and transform Catalonia when the existing government crumbled.