I think, these cards aren't designed to be the basis of many (if any) strategies. They are little things you can play for no cost and yet still, if you protect them, can be huge. By turn ten that's twenty ATK. (... assuming your opponent was able to survive that long, even >.> ) If you hit it with a buff it can easily be a force to be reckoned with. However, let's say that you started at... say... 2|4. The only cards that could kill it the same turn would be lightning bolt or shockwave. Plus it already has a one-turn head start and could easily be a gamebreaker. Now let's add the +3 to that: Turn one, 2 ATK. Turn two, 5 ATK, turn three, 8ATK. It alreadydeals as much damage as a phase dragon on just turn three, and it only cost 5 quanta total. Just one more turn and it surpasses even the light dragons. Hmm... I get the odd feeling I've been talking about this from a rather one-sided point of view, so let's look at the other side. First turn, it can be killed easy. Fire spirit is always killed easy so I'm going to leave that out of this next part. The forest spectre, if you can't buff it or grow it, it can be killed by just about anything. But that's the point of the grow. Plus it costs a different element to grow than to play, so maybe with this one start it off at 4 HP instead of 2. The fire spirit I can't really imagine needs a buff. Just ignore this if all this has been said already which, it probably has.
I'm AquaticImpalement and I approve this massage >:| (spelling intentional.)