I think the main benefit of a graphical language, as opposed to text-based is the rapid feedback loop. You see the response after every click.

This is the same reason so many people can build complex spreadsheets, yet wouldn't know where to start if you put them in front of an IDE.

I brought a book 'Computer coding for kids by Carol Vorderman' for a friend's daughters for Xmas (aged 6 and 8, both VERY bright with grades above their age groups). As learning to program makes you think differently, especially problem solving skills. It's gone down really well. Especially with older one who spends hours reading the book, even when she doesn't have computer access (and is now set on buying Chromebook with her pocket money).

A language such as Scratch is great for sparking initial interest, before going on to more depth.