I love chord keyboards as a concept, but I've never committed to one because I've been wary of acquiring a skill on such a specific device, and then not having access to one unless I bring it with me. Making a chorded keyboard a software solution is very appealing for that reason, especially if ASETNIOP were to become a standard approach.
For what it's worth, the first mouse was intended to be used in conjunction with a chorded keyboard when Doug Engelbart invented it in 1963: http://dougengelbart.org/images/pix/img0030.jpg
I've tried the online tutorial, and it's surprising how quick I've noticed some muscle memory for the most frequent chords (for letters r, h, d, l).
I think they've found something with the "always use the same finger as in QWERTY, plus another one". I was skeptical that users could ever adapt to a new layout, but this isn't exactly that, so it has potential.
The best thing is that it doesn't interfere with the existing skill on the QWERTY keyboard.
For what it's worth, the first mouse was intended to be used in conjunction with a chorded keyboard when Doug Engelbart invented it in 1963: http://dougengelbart.org/images/pix/img0030.jpg