Why are my customers unable to see the redemption button?
This article explains how you can solve display issues with the redeem button on your store
The redeem point button appears on the cart page, so when a customer who has an account with your store logs in with the email they receive rewards program notifications with, they should see the redeem points button on the cart page.
The reason why some of your customers are not seeing the redemption button is that they are trying to redeem their points from the overlay cart popup and the redemption button doesn't appear there.
To Resolve this:
You can deactivate the overlay cart popup so customers will go to the main cart page to make a redemption, or you can activate the Snow widget in your store that will make it easier for your customers to join the rewards program and make redemptions.