Yes, it's a great skill and I wish I had it. But it's like reading words. It's wonderful to think that you can pick up any book written in your language and read it just like that, and it must be fansattic to have that ability with music.
But if you found someone who had got so hooked on print that they couldn't carry on a conversation with other people without having the words written out in black and white, you'd know there was something seriously wrong there.