I absolutely see this. Just today I've been helping teach a friend's child to do multiple-digit multiplication on paper. In that kind of thing, understanding

I absolutely see this. Just today I've been helping teach a friend's child to do multiple-digit multiplication on paper. In that kind of thing, understanding place values (the ones-tens-hundreds columns) is so important. It's amazed me how many high school students even don't quite get the idea of place values and what base 10 means. The abacus requires a good understanding of that concept from the start. So, while the "skill spreading" might also contribute, with the abacus, it's a basic and essential concept to really understand for all higher-level math.