[sbrorson]

The reason Americans use cups and spoons (instead of e.g. grams) to measure ingredients is a matter of history. Tradition says Fannie Farmer wrote the "Boston Cooking-School Cook Book" in 1896, and for the first time in a cookbook used precise measurements (instead of "a jigger of this" or "a pinch of that") to specify how much of each ingredient to use. Nobody at that time would have a weight scale in their kitchen, so Ms. Farmer measured her proportions using tools which were readily available in any kitchen -- cups and spoons.

https://en.wikipedia.org/wiki/Fannie_Farmer

Her cookbook achieved immediate success and she became a household name in America. Even I had heard of her, long before I became a feeble student of history. Her measurement system is totally entrenched in American cooking culture, so I expect it won't ever be displaced by metric measurements except perhaps amongst high-end commercial kitchens and with people who want to make the effort to convert to grams and liters when cooking.