This is the first time I saw BTCpayer. Seems like I am already behind the development of this platform since the thread was made in 2018. Anyway, what is this platform all about? Is this allowed to all countries or there are countries that are banned to use this?
Another thing, what are the api? If you said that it is easy to install. I think it is efficient to use.
Its advantage compared to other payment processors is that it's open-source and you can run your own full node and accept payments through it. Meaning, no fees, no KYC needed, no blocked countries, supports SegWit, more privacy and security, supports Tor, LN, etc.
If you're interested in deploying it, read
the docs. Using a third-party solution might be the easiest way to go with if you are a newbie, but it comes with some limitations.