A flat earning rate treats every sale as equally desirable. Your business does not.
Some categories carry twice the margin. Some stock needs to move before a season ends. Some customers are worth considerably more than others and a uniform rate says otherwise.
Multipliers are how you express that without touching your prices.
What you can multiply on
Products and categories. Double points on the range you want to push. Useful for high-margin lines, for a new category nobody has discovered yet, and for stock with a date on it.
Customer tier. Your top tier earns at a higher rate than everyone else. This is what makes tiers worth reaching rather than just a badge.
Why this beats a discount
A discount reduces what you get for the sale, immediately and permanently. Once a customer has seen 20% off, that is the price in their head.
A multiplier costs you nothing today. It creates a future obligation, some of which never gets claimed, and the part that does gets claimed on another order. The customer’s reason to come back is the thing you handed out.
For shifting slow stock, "earn triple points" tests better than a discount of equivalent value, because it does not signal that the product was overpriced.
Stacking with bonus events
Multipliers and store-wide bonus events can combine, and you control whether they do. A triple-points category during a double-points weekend is either six times or a choice between the two, depending on how you set it.
Worth thinking about before a promotion. The combined number is easy to underestimate when you set the two things up a fortnight apart.
What the customer sees
The earning badge on a product page reflects the actual rate for that product and that customer, not the base rate. Someone in your top tier looking at a double-points category sees the real number.
Which is the point. A multiplier nobody notices is a cost with no behavioural return.