I think this is mostly a US thing. Why use yearly salary? You’re not paid once a year, are you? Most likely once a month. Referencing monthly salary makes much more sense.
“I’m making 50k”. Great, now I have to guess - dollars? Monthly? Yearly? If yearly then what’s the monthly paycheck? Net? Gross?
It does actually, because if you are any amount into tax bracket n, you are already implicitly paying the maximum taxes of brackets 1 to n-1
For example in Canada, federal tax brackets are:
If I say I am in the third tax bracket, that already implicitly informs you of how much taxes I am paying for the first and second brackets, because by being in the third bracket I already am paying the maximum amount for brackets one and two. These are now fixed values implicitly.
If I am in the third tax bracket, you know I am paying at minimum $8003.85 + $10938.39 (the maximums of bracket 1 and 2 combined), and at most another $20,371 above that.
No more, no less, the “third tax bracket” is paying between $18,942.24 and $39,313.24 per year.
So yes, it is a specific and fixed “range” of taxes.