"and recalibrated if you use a different-weight empty container."
That's called the "tare weight" and is usually set with a simple button press.
"i don't care if 'cups' isn't in a recognised system"
But it is. Or rather they are. Most countries have a standard measuring cup of one description or another. Even good old Blighty has one, which holds 10 Imperial ounces. Made a bit of a mess of my bread recipe when I first got to Yorkshire ... my own damn fault, of course. Once I educated myself, and converted my recipe (as any half-way decent hacker would) all was well with the world again.
A cup of butter here in the US is half a pound, or two sticks. No need to measure.