Websites is to industry leads provide valuable information to their target audience. As much as they are there to sell products and services, they are also there to inform and entertain. In the past, this function was fulfilled by newspapers, magazines and books (it still is, but the internet is now a big player too), all things you would.
Have had to pay to industry leads use them. Today, most websites provide extremely valuable information for free. Of course, for many sites this is part of their strategy to help sell their product or service, but what about sites where the content is the product? These websites have yet to find sources of income, and with memberpress.
Their content can industry leads become a major source of income. You can see examples of this on websites like the new york times, which requires you to create an account to read articles, or medium, which limits non-members to three premium articles per month. If your content is valuable enough, there's nothing stopping you from doing.