Are there pros (other than saving money on hosting) or cons to having more than one site on a hosting account?
Not really. The only advantage imho is that you can interlink between your websites IF you get a hosting account on a different server. Other than that, nothing.
Well, the con would probably be that you can't get individual control panels on different servers, and that if the one server goes down all your other sites go down, but the pro is that its all in the one account.