True, if you have literally $0 cash on hand then it could make sense. If you ever get your hands on $70 though that seems like a worthwhile investment to spend ~50% less time at the gas station for the remainder of your life. Probably one of the more cost efficient quality-of-life purchases you could make in my opinion, which is why I find it odd that it's not more common (apparently).

You aren't addressing the situation the people are in. They are constantly choosing which need to address with the funds they have at present, not simply deferring the purchase of one half tank of gas.

Building a small financial buffer would likely improve their situation a great deal. It seems likely that it isn't always the case that the lack of buffer is a choice...

Of course it is never quite that simple. When people are cash strapped and under stress, pure unemotional logic may not drive all decisions. Making a $140 purchase when you know you can get by in the short term with a smaller purchase just doesn't add up to a person in that situation.

But "time at gas station" is only like 3 mins per visit though. Yes it's not where you want to be but in absolute time terms it isn't much, especially if a gas station is on your typical travel route