Many of the chain hotels and restaurants are keen to roll out their loyalty cards or their shareholder cards with percentage discounts.
These are wrong on two counts.

Firstly the customers who use them tend to wave them around like a VIP membership badge, and demand all sorts of nonsense from staff.

Secondly it immediately gives the impression that you have a two tier system for customers, important ones and not so important.

ALL customers are important, and if you have been applying the methods written about here on this site, you will have so many customers anyway that you will not need any loyalty cards as they will be beating a path to your door and would not dream of going anywhere else.