[digsmahler]

I had the same question, the piano is already a well developed and standardized instrument from centuries of revision and engineering. Returning to one string seems like a step back into the past. The video is really nice though, explaining how they came to this idea, and now I want to hear one of these one-string pianos! From Nils Frahm:

"It really felt like a brilliant new instrument, it was so nice. First time in my life to have kind of like a new piano. It sits in between a clavichord, guitar and a harp, and that was exactly what I wanted."