How it is coded now you can easily add multiple networks manually for your pi to remember if you’re taking it to a friend’s house with a different network:

sudo nano /etc/wpa_supplicant/wpa_supplicant.conf

just add the following lines at the end for each new network (WPA/WPA2):

network={
    ssid="NETWORK_NAME"
    psk="NETWORK_PASSWORD"
}

for different encryptions like WEP you can see the wiki

As far as integrating it as an option in the setup script you can open up a ticket on github