Registering a domain and hosting one is often mistaken by a lot of people to be the same thing. These are in reality 2 different services - the domain registration is the actual name and nothing else, while the hosted domains feature refers to the amount of already registered domain addresses you can accommodate within the same website hosting account and have website files and emails for them. Your websites will work in precisely the same way no matter if the domain addresses are registered and hosted in one place or are registered with company A and pointed to company B. Simply registering a domain without hosting it will grant you ownership, but will not allow you to have a site if you don't host this domain in some account so that records for it are created and it starts opening the data from that account.