Not sure why this is being tested.
As mentioned by others, the acceleration and deceleration speeds with the power plant design would not be practical for routine passenger use.
Scramjets had been looked at for a space plane that would take off as a normal plane and use scramjets to break out of orbit. That idea has been repeatedly proven to be too complex to be practical. The Spaceship 1 / White Knight project proved there are more cost effective alternatives.
With all that said, I am not sure why they are still doing testing of scramjets. The only other application would be weapons delivery.
Sjdelay may have hit on its purpose with the question: Plane or a Cruise Missle?
In 2010 a prototype hypersonic rocket built around a scramjet, visibly similar to the X-51, was successfully tested. It was essentially a very fast cruise missile tested as a possible replacement to conventional ballistic missiles.
