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 France, people are sometimes paid 13/14 months a year. It means you get two months as a bonus, so it’s relevant in this case to tell the yearly salary
True, and funnily enough french people don't use yearly gross. Most of the time they use monthly net, and, in the context of salary negotiations, will specify over how many months. E.g. "2000 net sur 13 mois"