can be used.
There are other methods , eg. by masking you as a searchengine or a browser by using the browser's, SE's user agent. The reason is that humans are blocked, but search engines are allowed to find the content so SE's are allowed access.
The most secure payment method for your customers is to whitelist users / clients via a static Ip in .htaccess if your site is hosted on an apache server. In Norway there is a service called Vipps. It is simple and secure to send money directly to a bank account. Combining that with white listed Ip's, I personally do not know of a more secure payment solution for your website.
Your clients need to have a static Ip to get a whitelisted access. A dynamic or random Ip will not function.
By whitelisting Ip's, you have implemented an
.extra net
Video paywalls on your hosted platform, FaceBook, YouTube, Vimeo etc is getting more popular. It is also possible to get around video paywalls.
What is next? May be Intel on demand or your CPU behind a paywall.
Only serious semantic comments.