As a general rule, insurance will not pay for a package arriving damaged. The insurance company will claim inadequate packaging. The only way to get a damage claim paid is if the package arrived crushed by a truck tire and you can prove that the tire was on the carrier's truck.
Insurance will pay for lost packages though, but that's about the only thing.
So, to answer your question, there is little point in buying insurance. I self insure by putting aside a little from each sale. Over the years, my loss rate has been about 0.1% of my sales. Contrast that with USPS insurance which costs about 2% of the declared value of the package.
