This ignores the primary reason why I, and many other people who I know who travel frequently: reducing the amount of time spent traveling.

Checking a bag is another line you have to account for when arriving to the airport. It also means that you have to wait an extra 30 minutes on the far side to get home.

I happily check my bag, charge or no charge, if they found some way to get them to myself and the other passengers more quickly.