Registering a domain name and hosting one is commonly mistaken by a lot of people to be one and the same thing. These are actually two separate services - the domain registration is the actual name and nothing else, while the hosted domains feature reveals the amount of already registered domains you can accommodate in the same website hosting account and have website data and emails for them. Your sites will work in exactly the same way regardless if the domain addresses are registered and hosted at the same place or are registered with company A and directed to company B. Simply registering a domain address without hosting it will grant you ownership, but will not allow you to have a website 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.