ASICS centralize the power in the network to people with five to six figures of capital. GPU mining is more accessible and keeps the hashing power distributed.
Also, don't fool yourself on power efficiency. The network adjusts the difficulty, so if ASICS are 100x as power efficient the difficulty will tend towards 100x harder.
Also, don't fool yourself on power efficiency. The network adjusts the difficulty, so if ASICS are 100x as power efficient the difficulty will tend towards 100x harder.