It is cheaper but not always more practical. There is a zone between about 250 to 500 miles where GA is more time efficient unless both ends are at a hub.
Example: I live in Tampa, and have family in Savannah GA that I visit several times a year. There are no direct airline flights, so I have to change in Atlanta. Figure an hour to drive and park at the airport, an hour in security and boarding, 90 minute flight, 30 minutes on ground in Atlanta, and an hour flight to Savannah. Add it all up and the process takes about 5-6 hours.
It is a 2 hour flight in my Decathlon, which is not a particularly speedy airplane. It is a beautiful flight too, up the Florida coast, over the top of Jacksonville, and along the Georgia barrier islands.
For lots of people who live in more rural areas, especially in the midwest, going point to point via GA is way more effective than the airline hub and spoke model. Probably not an accident that much of the GA industry is in Kansas.