Maybe this exact method of release wouldnt be possible for larger UB sets to come, but the ideas of matching crossover IP to other sets in their release window, and of spotlighting their Universes Within versions, should have been carried over more zealously
Each of these legendary artifacts discounts spells of the relevant color, provides a useful passive ability, and has an activated ability that synergizes with its passive ability
This means that not only can you access additional cards, but you can reactively play the majority of the spells in your deck during an opponent's turn
Thankfully, there are still plenty of new Mega Evolutions from Pokemon Legends: Z-A that have yet to receive their own cards, including both versions of Mega Raichu, and the newly revealed Mega Garchomp Z
It gets better when you're dealing with a 187 creature, but it's fine even when all you're doing is saving your best guy from a removal spell
You also get a nice proliferate loyalty ability to boost multiple planeswalkers at once, and a great final ability to take an extra turn