This technique is easy to teach, and easy to learn too. Hence everybody wins, right? We-ell. Two problems, one small, one big.
Firstly, any errors made in teaching are very difficult to correct. I lied. This technique is deceptively difficult to teach. Unlearning errors is always hard. Secondly, and far more importantly, the Suzuki method is very good at teaching kids to play one thing, very well, fast, and accurately. Perhaps it is easier to understand if I give you an example. I write a document in, say, Word. I save it. The computer now (I know this is horrendously crass) 'knows' that file. Right? It can, theoretically and barring the perversity of printing equipment, print out that document an infinite number of times, perfectly and without variation. It cannot, however, write a new document. Because it doesn't understand. The Suzuki-taught child will not understand the music it plays, nor read notation, nor create music of its own without independant tuition in these fields.
Conventional musicians can often be found sneering at the Suzuki method because it lacks depth: it is learning the answers without understanding them. Whatever the weather, I'm not here to discourse upon the merits and demerits of differing types of musical education. I'm just pointing out that the Suzuki method has certain limitations. Despite these, it is valuable in that it gives pleasure to children through music, and for that, I salute it.