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?
At every job I’ve ever had, I get paid every two weeks. So the amount I make per month varies.
Those months where three paychecks fall in them are pretty sweet.