Most recipes are useless internationally anyway, the ingredients are often different locally or hard to source. If you're lucky and you have a kitchen in two different regions or, like me, you live in a non-English speaking country who still wants to cook dishes from home then it's going to affect you. That's a vanishingly small number of people.

Otherwise, most people will know how much an egg weighs, especially if they bake regularly.

The good news is that everyone puts their life story before you get to the recipe, so you'll know if they're American or not.

No different than US volume measure where you actually need to have the "measuring cups". Weight is still easier, as you can refer to the reference range of 'large' and reproduce it on a scale.