Yeah but he is still right when you go under surface level : learning to write is basically learning to draw specific shape that have specific meanings.

It is not surprising that peoples learn to recognise those shape faster when they actually had to learn to draw them instead of just pointing (typing) to use them.

But I don't think it makes any kind of real difference to achieving proficiency level for reading/thinking/writing the language. Recognising the glyphs is a small part of learning a language, you learn grammar, vocabulary, sentence construction, idioms, mostly by repeated exposure and chances are the vast majority of it is from reading ; it wouldn't be very efficient to learn by hand writing everything...