Sorry, I'm confused... Why does this use 와? Because of the final vowel? If that's the case, couldn't 하고 work as well since it has been used with words that end in a vowel? Or do certain words take certain particles?
As far as I can tell (not very far), when a word ends in a vowel, you are free to use either 와 or 하고. The tips/notes for the Basics-1 unit suggest that 와 is common in writing, and 하고 is common in speaking.