This device provides for you the
one-hand equivalent of what you could do with a keyboard.
There are five keys. And normally each finger sits on
a key and, depressing any one key at a time, produces
a character, and any two keys at a time also. And, in
fact, any combination of depressing, of which there are
combinations, will offer you a character.
And the thing it does is, while you're
moving the cursor to point to some object, by the time
you click on it, you've usually told it what you want
to do. And this makes it very different from going and
selecting it, and then, in some contortion, telling it
what you want to do.
In fact, there's enough time not only
to say what you want to it to do, but what class of object.
I want it to delete that word. I want to delete that whole
paragraph. I want to delete that whole branch. I want
to copy that whole branch. So those are all set by the
time you get there. So it's as much faster and more flexible
as a bicycle is from a tricycle.