Quest for the royal dragon egg

[Xargon]

Does anyone know if there is an upside to helping the griffins steal the royal ice dragon egg? Do you encounter the griffins later on?

The immediate consequences are:
Helping the griffins: Both shops gone, you fight two dragon heroes (second fight optional).
Helping the dragons: only one shop gone, you fight the griffins, additional scrolls and an item as reward, followup quest which will reward a Dragon Slayer's Sword (not sure if this is fixed, and it is probably almost useless after this point. But it's shiny).