You can connect it to Networks so People connect to the Pineapple ( is has a higher connect priority if u set it than the other hotspot). So say ur in Starbucks.
Connect the Pineapple with the Starbuck hotspot and People will connect to ur Pineapple (4 more Connections u can rename ur Pineapple access piont Stanbucks or smthn).
Now ist just an Access Point wich extends the Connection range but thx to the modules u can install on the Pineapple and ist Ground Features u can now do different Things to the Clients wich r connected. For example u can steal their Passwords if they log into smthn, u can see wich Websites they r on, wich Cookies they get, and so much more...