You're not wrong but there are those that do not succumb to $8 airport beers. And not fretting over a few dollars lost to exchange rate would not have saved you that $16 but added to it. Being thrifty or not is a mindset and usually not confined to one thing. Once you start justifying bad economics those "few bucks" can quickly add up. There are those that don't care whether their Coz trip cost $1500 rather than $1000 but I view it as being able to take 3 Coz trips instead of 2.
If I had that kind of thrifty mindset, I might already have saved enough to retire and visit Coz as much as some of you do!