What makes the card so interesting is that it was an unreleased Promo Card in Pokemon TCG Pocket, and its developers hadnt said a word about the mysterious item piece for a long time
If you have other cards that you're more likely to cast on your second turn other than Luminary, then you should treat it as a four-mana spell, as that is when you are likely to cast it
This means that almost every time the front side is cast before and the two sides have some synergies together, which isn't true of split cards where you can only cast one or the other
Each card links to its full details page
I do quite like it, but I definitely agree that I think he's going to require a good bit of draw/hand manipulation to make sure you can actually curve out with him properly and not have a high chance to just end up with a hand that you can't work with
Due to this, if a card below catches your eye, it's worth selecting the right starter pack