it's should be I guess, a possibility to add product discounts for all users or group of users. You could add field 'type' for example to coupons in order to create such a discount, which will be visible to clients, without the need to fill coupon code in basket. Are you planning to add something like that?
now you have two options:
1/ each product category can have sale for a customer (eg.: 20% for mobile for me :)
2/ or each product can have individual price for each user
I think for you it will be good to use sale in category.