Patents are granted to guarantee exclusivity for a 20 year period. Without these protections a company would not invest tons of cash designing and developing anything. My company for instance spent 8 million dollars to develop a product that can be mass produced very cheaply. We have to recoup the investment. If another company buys a copy of my product and copies it, they can then make and sell it for less than me, because they haven’t spent the 8 million bucks that needs to be earned back. Without these protections there is no incentive to invent. Patents are a double edged sword. They give protection but at the same time the entire process for making the device must be fully explained and detailed in a document that is readily available for anyone to read.
International patents trump US patents, I was told.