I'm sure that people suck at math and that indeed the conclusion of the article are mostly correct. However, there are genuine cases where getting more is more

I'm sure that people suck at math and that indeed the conclusion of the article are mostly correct. However, there are genuine cases where getting more is more cost efficient than a discount. It all depends on the quantity you need - sometimes, a little bit more is just all you need to avoid buying 2 units. Especially in the UK where you almost never get 33% discount but instead "buy 2 get 1 free" offers.