I mean, its annoying if you manage to forget both (as I have done on many occasion), but usually you can get away with just one
It is also one of those more castable ones for bonus value
That means she reduces any damage being dealt to her by 1 point per Knight you have on your side, which surely means were going to see some Knight-focused decks in the meta, taking advantage of this excellent ability
Well, getting them as a Christmas gift, of course
To do this, you position Dialga-ex in the Active position and use the attack Metal Turbo with two energies to transfer energy to Arceus-ex
Thankfully there is a banned and restricted announcement this upcoming Monday, and not only is some kind of energy ban expected to happen, there could even be a substantial ban across the mechanic hitting multiple cards