Except a single infect creature doesn't work on it's own in a deck, that is trying to win by damage. Aether Swooper does. It could instead have charge counters placed on itself and "when ~ attacks, you may remove two charge counters from it. if you do, create a servo" to be almost the same card in my cube (the onl real advantag being that you don't lose the counters when it leaves the battlefield for recursion and bounce purposes).
So while energy could be parasitic, the way they designed it isn't so much. Their power level increases with more energy around them, but they do not work contrarily to what the rest of your deck tries to achieve.
So while energy could be parasitic, the way they designed it isn't so much. Their power level increases with more energy around them, but they do not work contrarily to what the rest of your deck tries to achieve.