For one thing, your hubs are already automatically shared with your followers when you publish them.
People may also see them again, when you reply to followers who comment-- in the feed.
A few hubbers have made a habit of sharing their hubs --one after another, again and again-- which pretty much falls under the category of 'self- promotion", and gets a little annoying and tiresome.
These are just my theories. For a more definitive answer, a staff member would have to give you a reply.