What is the "world" key for on the iOS keyboard?

When I turn the iPhone sideways while in text editing mode, I get the extended keyboard. There is one fairly large key there (which I am always hitting accidentally) that has a "world" or "globe" icon on it. When I tap that, it shows a "head and shoulders" icon labelled "name."

What is that for? I see that it types my name, but I don't see why I need a huge, special key to do that.

There are also character keys, such as #, ., ? etc, which are already on the standard keyboard. Tapping on the 123 key there brings up the number keys, which, again, are already on the standard keyboard.

Is there some special purpose for all this that I am missing?