My main struggle with BASIC at 10yo was its non-strict SQL-looking structure. Maybe that’s me specific, but this gradual thing would be even more confusing, cause it gives nothing rigid to pattern match against. The big part of it is demystification and regularity. I only started programming when I got Turbo Pascal (and god bless BGI). Before that it was all muddy waters.
I was very confused by the complex structure of Pascal (in Delphi). I think everyone has their own way of struggling with their first language.
I have doubts whether the gradual language is confusing or sensible to the average brain. Only time and competition in these kinds of educative tools will tell.
But, there is one thing I'm very sure of: the more kids that get to experience the joy of creatimg something by programming, and the more kids that get to experience the feedback loop, the better!