What it teaches
Hearing a word and writing it down. It needs the sound, the spelling and the keyboard all at once, which is why it is last: a word that can be spelled from hearing it is a word that has been learned properly.
It also quietly teaches English spelling, which rarely matches the sound. A child who has typed cheese a few times stops expecting it to look like it sounds.
How it works
The word is spoken and an on-screen keyboard appears with the letters. The child types. The word can be heard again at any time.
A wrong letter is not accepted, and the word stays. On the gentler settings the right key lights up after a long pause; on the strict ones it never does.
What to look for
Expect this to be slow. A child who is quick at Listen and pick may take three times as long here, and that gap is the point of having both.