It is not about confusion, it is about convenience. I like the idea that water boils at 100°C since it is maybe the most important temperature in cooking. I like the fact that I can measure 500mL of water on a scale as 500g (and other liquids with a small error). Small details that make it more convenient in metric.

But there is something else, and I am asking you the question. Since you and your wife live in countries with different unit systems, isn't problem when doing each others recipes?

I mean I live in Europe, and if the recipe calls for 4 ounces of butter, I don't have a 4 ounces stick of butter, I have a 125g stick, which is not exactly that. A quart of milk is not exactly the liter I have. And my oven doesn't do 350°F, it does 180°C which is not exactly the same. In the end, I will have to adjust the recipe to my standards, and things may be lost (or gained) in translation, but it won't be the same.