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?
In my last three jobs, I was paid weekly, then bimonthly, and currently every two weeks. Weekly and every two weeks is easy to convert, but bimonthly my pay would fluctuate slightly.
There are also yearly bonuses and similar that would not be included.