Well if you took the price of a vault of crystals to find the cost of maxing Leia through shipments you get around $168. ($99.99/15710)*26,400 crystals since you need 330 shards total
It definitely would take longer than opening mass chromiums but in the long run you save a significant amount of money. This method is for people that want a p2p character without participating in the chromium lottery. It's not a feasible way to get p2p characters for f2p players without crippling progress in other areas.