They aren't very informative when you don't take into account the differences in local/state/national tax rates, purchasing power, cost of living, etc.
You need so much more information to get a decent picture of how much better or worse a job offer is relative to what you currently are getting.
For instance, 60k in some areas of the USA means you are living like a king, have acres of land, a lake, multple cars, etc. That same amount in NYC probably makes you homeless.
Whenever I go to the US it's shopping time. Pretty much everything is cheaper. And many items you just can't get elsewhere (which is another aspect many ignore).
I know this is going to be controversial, but healthcare-wise high earners might be better-off in the US too. Generally it would seem to me, the more money you make the better US is in comparison.
Believe it or not, I'm only saving 3 dollars an hour of my pay. That's about $6300 a year because I work about 2100 hours.
If you account for commuting time and emotional/physical toll of working, I'd say it's nearly negative pay.
Saving money isn't just about making more money, but just as much as cutting expenses.