The author states:
Prior to joining the Snap! project, I had spent 20 years teaching computer science using the best computer science book ever written, Structure and Interpretation of Computer Programs (SICP).I have also taught high-school aged students using a modified version of SICP, Picturing Programs [1], and have had a very high success rate. The students have been able to comprehend topics like recursion and functional programming as a natural progression of learning. After completion of the course, they are able to pick up other languages like Javascript and Python rapidly, given the fundamentals they have learned.
The question I have, which I could not find an answer for in the article, is why Snap, or any visual programming language, leads to greater successful outcomes than using SICP and Racket? Even if you agree that Scheme/Racket has limited practical value in the workplace, I have found that students who learned these languages have a much greater facility to learn other languages. Courses that I have taught using Javascript and Python have not given the students that same ability.
Students who I have taught using Racket and SICP have a much deeper understanding of the fundamentals of computer science and they pick up these fundamentals in a much more organic way.
[1] http://picturingprograms.com