Nowadays, trade is generally unfair and we want to improve it. That is why ZDX was created. Socialist capitalists torture the poor and middle class of people in the economy based on credit. It describes as a transaction between a lender and a borrower, in which the borrower promises to pay back the money in the future along with interest.
So this idea of interest was developed for ZDX to share our income with all investors. It's just simple, you invest and receive interest from ZDX revenue.