Living Energy 0003_MTGDFT_CommFace: Saheeli, Radiant Creator 0002_MTGDFT_CommFace: Pia Nalaar, Chief Mechanic Check out the cards from Living Energy in the Aetherdrift Card Image Gallery (tokens and helper)
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The main reason was and is to retain the value of those cards on the secondary market
It's colorless so it can slide into any deck out there
The exception is Sleight of Hand to try to find Lotus Bloom on Turn 1 in Ad Nauseam, with the flip side being many decks having an important two-drop to find like Baral, Chief of Compliance
Boosting your team with +1/+0 means your creatures always swing above their weight class, and every time one dies, Judith gets to ping any target