You should get a refund for the postage and compensation in the form of the base insurance amount ($50?), unless you paid for more than that.
I’ve had very good luck mailing things with tracking numbers via the USPS. Of course, I wasn’t (disguised, in cash and fake-return-addressedly) mailing pound boxes of fecal matter to my congress critter, either.
I can’t say I haven’t been tempted.
There is no insurance on documents.