I would say that first and foremost hubpages offers a writer a place to showcase their work and to build an archive on the Internet of their articles and stories. It means your work will get seen, although obviously the more you promote it the better.
All sorts of people can come upon your hubs when searching for info on line. For example, the film-maker Chris Everard, whose Feed Your Brain magazine I now write for, found me when he was looking for information on the Kogi tribe.
Secondly, hubpages is a great place to make friends. The community here is very helpful and if you are looking for advice or help you will find it on hubpages. Use the forums for this and get to know fellow hubbers by reading and posting comments.
Then of course, it is possible to make money here but you will need to work hard at it, you need to be patient and not expect instant results, and I would advise that you read the hubs by the top hubbers and high-earners to see how they have found success here.
Good luck hubbing!