Whats the difference between egg bag and boxed egg?

Was just digging through cq_itemtype and cq_action and kinda don't get it.
Say, for boxed MageM-def (ID 815010) there is action 4008150, while M-def bag does not have normal action ID but hell knows what.
Any tips how it works?

Is 2 different items and used for 2 different things.
They are might both used for any kind of event, but maybe not same time :)

i gues if the bag has no action .. the bag wont work?

or the bag is itself a egg and not a bag