How do these supplement cpa offers compete with amazon ?

So i am taking my first steps into cpa marketing and doing some casual analysis.
right now i am roaming inside maxbounty and peerfly.

i see that health supplements is a big niche with lots of "problem solving" medicinal products like piils to heal nerve pain, joint pain, hearing problems etc. i am aware that supplements is a big business.

But there are plenty of similar products on amazon.com as well.
How do these cpa offers compete with products listed on amazon.com.