Haha, nice timing that this appears after the "why are airplanes so hard to build?" article! Putting the engines to radiate sound upwards does make a lot of sense.
I was intrigued, but acoustically it doesn’t make a lot of sense really…the thrust exhaust where all the fast moving air comes out, also happens to be where all the loud comes out too. Their renderings don’t look like the engines are far enough forward for the fuselage to provide any significant obstructions to the path of sound from the exhaust down to the ground.
There's also the issue of ingesting the turbulent/detached boundary layer of the fuselage at high angles of attack, causing inlet distortions and the corresponding risk of compressor stall.
Also safety. Uncontained engine failures shouldn’t ever happen (and maybe happen less as technology gets better), but when they do happen, it’s better for them to be under the wing away from the fuselage rather than right in the path of critical control systems.
Since this is a blended wing with no vertical stabilizer, it might be different, but it does still look like there are control surfaces right next to the engines..