Well, since he supposedly spawns for you only when you maxed out your event store, you won't need any more currency.
You might not want to take part in the fights against those bosses if you still want the currency, true.
Although since he has a chance to drop equipment spirits, for me it would be a priority and would choose him over the earlier bosses to fight.
I meant the Great Shogun Spider, that mega94all was talking about.