Private pilot, recreational, and sport pilot licenses are useful for flying in beautiful, VFR skies for excitement, adventure, and leisure.
Many people opt for the recreational/sport pilot licenses because they are "easier" to get than the private pilot license. This is because they require less hours than the private pilot license, and therefore less money and time... hypothetically.
A recreational pilot license only requires a minimum of 30 hours of aeronautical knowledge (FAR Part 61.99) and a sport pilot license requires only 20 hours (FAR Part 61.313). These are low hours compared to the 40 required for the PPL.
Because of the lower hour requirements, you can spend about $5,000 to earn a sport license. However, rarely do pilots have the knowledge and skills necessary by those required hours. Often they need to spend more time and money on additional hours for more practice. Then, it can take upwards of 40 hours to earn the licenses, and in this case, you're almost spending the same amount of money it would take for a private pilot license.
If a student was going to spend thousands of dollars on flight training regardless.... would you choose the license with more limitations, or less? You would probably choose to get the most bang for your buck and opt to have less limitations and MORE privileges.
Limitations of a Recreational/Sport Pilot License(FAR Part 61.315):
Can fly for business business or pleasure
You can only carry one passenger
May not fly at night
May not fly in B, C, or D airspace unless you get the endorsement and additional training
May not fly higher than 2,000 ft
Always must have ground in sight
You will more than likely be spending more than the minimum average of $5,000. While the cost of a PPL can be around $12,000... isn't it worth it to be able to fly more than one passenger, higher than 2,000 ft, fly at night, and fly in all airspace (must have IR for class A at 18,000 ft).