Payment links come directly from Stripe—they have their own settings.
Readymag’s checkout page does not support all aspects or Stripe’s catalog. It is a simple integration meant to sell a digital goods mostly.
You can play and have both options inserted into your project but it is far from ideal as payment links do not communicate with the widget’s features (like the Cart).
If you main focus is providing a larger set of payment options, I guess it makes more sense to stick with payment links only.