Why i must add funds to my account?

When i try to buy item with added discount code, checkout change to option to add funds instead to authorise payment through paypal? Why is that ?

Items priced below $10 or over $100 require the user to add funds in order to purchase it.

I too was a bit confused and ranted about it initially. but then the more i used it it seems logical sense. It’s easier to have gameflip wallet and from my understanding as time passes by and you make more purchases , the limit to add funds to your wallet increase as well.
Do you have any grievance against using that way?

No, i just asking because i didn’t know