pritnln!("{}", Amount::from_sat(50_00_000_000).to_string_in(Denomination::Bitcoin));

Expected string: 50
Got: 50.00000000

This needlessly burdens users with meaningless zeros and causes BIP21 URIs to be longer, wasting QR space.

Ideally we would have struct DisplayInDenomination(Amount, Denomination) that impls Display with all the bells and whistles but for starters making representation minimal is fine.

I think this is easy enough for good first issue.