Getting data to literally the other side of the globe currently takes about 100 milliseconds. How many truly novel applications open up by that latency dropping to 66ms?
For short-distance stuff the latency is already low enough to be practically realtime. For long-distance stuff we're already fast enough for human-level applications (like video chat), but it's not dropping enough for computer-level applications (like synchronous database replication).
I'm sure some HFT traders are going to make an absolute fortune, but I doubt it'll have a huge impact for most other people.