The article explained it fairly well. Re-iterating the credit card churning example: people will spend a lot of time optimizing their credit card spend, to end up with maybe a few hundred dollars in savings per year. Working 10 hours of overtime a year nets more and takes less time/mental capacity, for example. But it is fine to do this anyway if you let go of the "I'm saving money" schtick and just embrace that you like maximizing points on spend.