Any characters that have been welcomed can be leveled up after the event ends - using regular magic potions instead of event currency. And it gets a little easier to collect the common token (the 1/2 teacups in this case). The lunch boxes will go away, and the quests will give the common token rather than a key or heart lock. But there may be fewer characters with these quests.
Another thing to consider is they usually convert your remaining event currency to gems at a rate of 1 gem for every 2,000 event currency. It's limited to 40 gems for 80,000 currency, but it sounds like most people aren't going to have that much extra for this event.