Quick Answer
Butter does not use the same grams-to-cups value as every other ingredient. Using a practical US cup reference, 227 grams of butter is about 1 cup.
That means 100 grams of butter is about 0.44 cups, while 200 grams is about 0.88 cups.
Butter behaves more consistently by weight than many dry ingredients, which is why many baking formulas prefer grams.