Answer:
The ability to have flash-like speed!
Explanation:
1. You could get to any place to Earth conveniently, whereas being able to fly only really sends you upwards where you could eventually run out of oxygen.
2. You could become famous and take part in the Olympics for example, whereas being able to fly can be seen as a magic trick or abnormal.
3. You could break through solids without feeling much harm because of all the energy rushing through you.
4. You can easily transport things, which could potentially save lives, e.g. rushing blood packages or medical aid faster than ambulaces, or moving someone out of a busy road.
5. You could star in a movie as a superhero without needing a stunt double or CGI effects, making you a very expensive actor to hire!