Who used these services?

nowpayments.io
coinpayments.net

Can you trust them? Since I want to integrate accepting payments through them, isn't this a scam?

Greetings to all developers!
Recently stumbled upon a cryptocurrency DAI coin. Yes, I looked at the repositories on the main developer site, but there are few examples. In connection with this, the question

Can I accept this stablecoin on my website, without using merchants and other things?

And what stablecoins can you implement to be accepted on your website, without using merchants?

Thank you in advance for your response!