Netflix (who are part of the group developing this) have stated they'll roll it out in production once it's less than 5x slower than VP9 so we can assume they are planning on it getting at least 134x faster than it currently is.
Obviously, they won't be able to roll out high resolution content to phones, TVs or set top boxes until devices support it with hardware, which will be a couple of years from now.
But, there's plenty of people in the world with decent desktop power and terrible bandwidth who can benefit immediately from squeezing better video through their connection at the cost of more CPU at both ends.
Generally you won't hear those people commenting on forums like this, but they show up in companies like Netflix's business plans. YouTube has produced maps showing which countries had greater usage due to VP9.