Not bad at all for an entry-level camera. Of course, colors are blotchy, details lost, and noise is visible, but for 4x6 prints ISO 12800 will useable. I expected low light performance to be much worse.
Great shot to show how the camera image processor works under demanding conditions. You have high ISO, bright highlights and dark shadows. It gives us a quick view of DR under high ISO. Perfect shot to illustrate that!
High ISO fast shutter speeds under closed apertures is hardly a demanding condition.
So, the purpose of this shot is to show quality at ISO 12800. It's not awful, although we can see some color blotching in the gray area at the top. I guess this picture serves its purpose. But what it doesn't show is a need for ISO 12800. 39mm could be hand-held at 1/50 second. That's 4 stops down from 1/800 second. So the same picture could have been taken at 1/50 second at ISO 800.
It really doesn't in a real life situation. Sensors are more hard pressed in worse light, and having 1/800 at a slow aperture doesn't suggest a struggle with light.