With the largest trunk, seating for five, and the most comfy ride the challenger is the most practical of the bunch. I think what you meant was the challenger is not a contender as a sports car. It does fine as a muscle car. The mustang has bridged the gap into becoming a full fledged sports car while the camaro falls in the middle.
Challenger wins as the most practical for free way travel. Impractical as hell maybe in a large city like NYC ATL or CHI, if that's what you meant.
It gets the worst mileage, its the heaviest, its the slowest (even the SRT 8 loses to the 5.0 and SS at $10k more), its the worst at cornering, its sales are fractions of what the Mustang and Camaro have been selling like, and its priced the highest..
Thats why I think it is impractical. Most people who are buying new age Muscle cars want them because they are quick, get decent mileage, and don't break the bank not because its a combination of a Muscle car and an SUV.