how HFT works is you co-locate a server next to the exchange in a couple of meters of proximity. there are an army of PhD's working on the lowest latencies possible, approaching compute cycle level (<100 ns = 1e-07 sec).

if you want to do "HFT" speed of light is by far the most important factor. if you pick two locations on the surface of the earth at random the maximum distance is ca. 20'000 km. with a dedicated line you get a factor of ca. 30% of speed of light (fibre optic cables in labs achieve 99%*c), which implies a latency of 0.2 sec ( = 1e-1 sec). and if you do TCP packets you have latencies of 1-2 seconds which is seven orders of magnitude away from HFT. so trading over the internet to a random server has nothing to do with HFT. there are possibly other ways to get to at least stable 1 second latencies, which the bitcoin exchanges don't achieve. the internet's transport protocol (TCP) doesn't care about latencies. CDN's and other infrastructure partly solve this problem, a rather new development.

incidentally if one has studied this one understands why bitcoin uses blocks in the first place. it's impossible to coordinate time under a certain scale. which is the reason the GHOST chain selection algorithm suggested is nonsense (IMHO). it takes quite a lot of experience with these things, which is why I believe satoshi was working on bitcoin for 10 years+. There is evidence to suggest he was working on it since the late 80's. I do support the idea of alternative cryptocurrencies, but more humility couldn't hurt.