In theoretical terms to say unlimited hosting services is not possible since you do not get an unlimited hard disk for your computer. Web hosting providers presume not all their customers will require all the resources. There are several small businesses and individuals who do not consume the resources that are offered and this number generally is more than the users who consume all the allocated resources. The
web server provider offering unlimited hosting package thus balances out the left over resources of consumers who use less resources and compensates it with those who consume more. The hosting provider does not lose anything by offering unlimited package. There is no catch behind the offer and you just have to look out for any type of clauses that they would have put up. You do not have to opt for the unlimited package if your consumption is low. It ultimately depends on your website requirements of space and
bandwidth. You cannot afford to have low resources lest your server may slow down or crash but you also need not invest on an unlimited package if your resource consumption is low and if you think you can manage with a lower plan.