This stuff has been developed here at IEM Graz (Winfried Ritsch, Automatenklavier, assisted by Thomas Musil), I’'ve seen it in a number of live performances with different pieces by Peter Ablinger - organised concerts with it myself - and I can assure you that the effect is that stunning.
This of course needs tweaking of the “right” granulation, sufficiently high bandwidth (OSC) and - this is also mentioned in the German comment - the projection of the text, which makes a big difference for the complement by our brain.
Find some links on Ablinger’s site (funny: the Schoenberg letter):
BTW Voices and Piano with live piano is equally stunning