Do you have a website? Or have you heard about membership sites? Chances are, because membership sites are found everywhere. It is every requirement for sites owner to be able to put restrictions to their sites and use different WordPress membership plugins.
Now that you have made a website using WordPress, you probably want people to stick around and use it right? Well, if you want to keep people on your WordPress website, especially if it is a social platform, then you have got to allow them to easily create profiles.