Not as helpful as they might think

I'm reading Helene Tursten's The Glass Devil in translation from the Swedish. For some reason, either her translator or her American publisher felt the need to footnote the words kilometer, meter, centimeter, kilogram, degree, and krona, and provide conversion units.

Except for the money, I didn't need that. It would have been much more useful if they'd footnoted and converted other things. For instance - how expensive is "a relatively new black Skoda"? Is it a Chevy, a Datsun, a Honda, a Nissan, a Porsche, a Jag? That is, what does it tell me about the owner? And the money could have been handled better, too. Sure, it was helpful to learn that a krona is about a dime (or was when the book was written), but what's the purchasing power? When I was in the UK last, a pound was about two bucks, but bought about as much as one. So is 8,000 krona like $800, or can you buy more (or less) with it?

Anybody can memorize the kilometer-mile and Fahrenheit-Celsius conversions. If you're going to offer us footnotes, you might consider what we can't know so easily.