I see this type of reasoning a lot and it feels like it should have its own named fallacy. A tiny percent savings on a huge cost is a moderately big number, yes.
The problem here is that you've switched from proportional thinking to arithmetic thinking in the middle of the thought.
In most cases, if you started with proportional thinking, you should stick to it.
Example of the fallacy: 0.1% of my salary goes to avocado toast, which might not seem that much, but over ten years, that's a thousand dollars!
The fallacy here lies in the fact that a thousand dollars is insignificant over 10 years, but the statement makes it feel significant by switching from proportional to absolute.
"The avocado toast fallacy"?
The problem here is that you've switched from proportional thinking to arithmetic thinking in the middle of the thought.
In most cases, if you started with proportional thinking, you should stick to it.
Example of the fallacy: 0.1% of my salary goes to avocado toast, which might not seem that much, but over ten years, that's a thousand dollars!
The fallacy here lies in the fact that a thousand dollars is insignificant over 10 years, but the statement makes it feel significant by switching from proportional to absolute.
"The avocado toast fallacy"?