I'm spending 700 cp per day on this event. Funny enough.. this actually get me more power than great plates per cp spent.. as other than oil cultivation (which is pretty slow at page 10), nothing else in great plates do anything for me at all.

If you want cave keys or medium refines, this event is actually pretty good, (more efficient than buying cave key gift packs tbh.) If you just want fragments.. then yea.. better look elsewhere.