Not offering snacks or drinks is disappointing, but I don't understand why you feel undercompensated. Yes, you were delayed 3 hours, but you were going to spend those at the Denver airport anyway when waiting for your connecting flight.
If you can combine the vouchers (not sure as I've never seen them before), you can fly BNA-TTN and go to New York or Philly for the weekend. There are several dates in May/June with tickets $115-$138 round trip.