Yes. It's all about profit margins. If I give 5% loyalty points that's fine for regular priced products. But if I also offer the product with 15% off for 10x or more, then I don't want the customer to get an additional 5% on top because my profit will be gone.
Yes, it's not related to loyalty points. But it's the same issue as above, i.e. I'd like to offer customers a 15% discount coupon for the whole store or even just for product X.
Now, product X already has 15% discount when you buy 10x or more. It's OK if customers use the 15% discount coupon for 1x product X and for 10x product X. But if they get 15% off of 10x and then additionally 15% there won't be any profit left. So only one discount should apply, ideally the higher one.