The advantages of the larger fuel tanks are increased range, fewer fuel stops and less trips to the gas station. My '05 QC SRT 10 had a larger tank as well as my F150 Harley Davidson 6.2 (36 gallons). I liked the bigger tanks.
When I think about complaining about the cost of gas I remember my motor coach has a 162 gallon diesel tank that averages between 5 and 6 gallons per mile. I think I'm justified in complaining about that.
I once had a Jaguar that had a 21 gallon tank and averaged 24 MPG. I really liked that. Sometimes I could go over 500 miles without a gas stop.