You can do this at instant speed, letting you sneak some damage through your opponents who might not be paying attention to your open mana, and very likely, not to the abilities you have tacked on those lands
Many energy cards are primarily designed to be one or the other, and exploiting the differing rates of returns between them using the efficient generators to fuel the powerful outlets is a big part of deckbuilding around this mechanic
I was very happy with the experience and if I ever have an unwieldy comics collection that I need to unload again, I will happy bring it in
A player may have two commanders if each of them has the partner keyword, with the two partners together combining their color identities for the deck
Any player may activate this ability but not while Kain is attacking
By comparison, an equipment deck doesnt feel all that unique (case in point: The Final Fantasy Starter Kit has an equipment deck with the same exact color combination)