A great advantage of using plaintext accounting is to track expenses. Why track expenses? One reason is so that you can get the maximum return for the money you spend.
And one way to make your money go farther is to comparison shop. If you can get exactly the same item, but at one place it’s twice the cost as at another, why not reward the vendor who has found a way to sell at a cheaper price? This assumes, of course, that the vendors are otherwise comparable. For example, one isn’t selling stolen property, but you get the idea.
In order to comparison shop, you have to compare prices. But have loyalty programs blurred our ability to see the prices?
For example, if grocery store A is selling milk at $5 per gallon, and grocery store B has it for $4 per gallon, that’s easy enough to compare.
However, what if grocery store B has a yearly membership cost of $55? And store A has a yearly membership of $80, but has a $5 coupon you can use each month as part of that membership. And at store A, you get points for every dollar that you spend. And the points can be used in various ways for free items or discounts on future purchases. And you are not only buying milk but hundreds of other items over a year. How can you effectively comparison shop? It’s going to be a lot of work as opposed to just looking at the difference of two retail prices.
Another problem, I believe, is that there is often a “feel good” effect when you get rewards in a loyalty program. When you obtain something for “free,” your brain gets reward signals. At least mine does. And an emotional feeling about a price can lead to mental accounting instead of plaintext accounting.
To summarize, rewards programs make it harder to know the actual price of something. And you can’t effectively comparison shop if you don’t know what that thing costs you. I don’t have a solution to suggest, but sometimes knowing what a problem is is the first step towards finding a solution.