Although green doesn't have great ways to deal with creatures and no way to effect peoples libraries, hands or the spells they cast and therefore qualifies as light on disruption green can deal with all other non-creature permanent types quite efficiently
It's the flexibility of the proliferate keyword that makes Atraxa such a versatile Commander
Its a great card, and often most effective, but I dont believe this line of thinking is correct as often as we think it is
I think the card would be a lot better if the it would be a simple light cone and not that wild as its a bit overwhelming a drains a lot of detail from the art
Bit of a missed opportunity, but maybe the goal was to ensure the challenge decks unlocked earlier on were still manageable for a new player
But most importantly, as its name suggests, this card provides flying to the creature which, in many situations, means your creature is unblockable