I am in South Africa, and we mostly use grams and ml for measurement too. The cups (and teaspoon/tablespoon) is just a more “informal” way of measuring I think – it all depends on what your recipe uses. But for butter (unless melted) and dried fruit, etc. weighing will obviously be more accurate. I think weighing is probably the most accurate way of measuring in any case, as long as you have a good (electronic?) scale, especially for baking, although I grew up with using cups in many recipes (especially hand-me-downs) as well. If you are not sure about conversions (i.e. your recipe specifies cups/tablespoons and you want grams/mls), I find that doing a quick search on Google usually gives many conversions – sometimes this is just easier than for instance measuring out 8 tablespoons of something. This is also handy for finding out how many grams of a specific item is in a cup for instance, since it will differ between flour, sugar, etc.