If those figures (93Gb/s) are right and represents a real-world scenario, and not a lab test, then it's really impressive.
The following quote from the article highlights the difference between HORNET and Tor:
"Unlike onion routing protocols that use global re-routing through overlay networks (e.g., Tor [23] and I2P [47]), HORNET uses short paths created by the underlying network architecture to reduce la- tency, and is therefore bound by the network’s physical intercon- nection and ISP relationships. This is an unavoidable constraint for onion routing protocols built into the network layer [29, 42]."
Latency vs. anonymity is usually a tradeoff: if you monitor the whole network, you can correlate flows between nodes, and this gets easier with lower latency. That's why Pond connections are randomly timed. They acknowledge this fact in section 5.2:
Flow-dynamics-based end-to-end correlation.
In general it is difficult even for high latency mix networks to resist such powerful adversaries. Low-latency anonymity systems are particularly prone to these types of attacks. HORNET cannot protect
against them, but as mentioned above, the use of packet obfuscation
makes these attacks more expensive and allows for potential additional measures to be taken (e.g., padding), either by upper layer protocols or by extensions of HORNET.
They would see that you were communicating (because by necessity, all your stuff passes through them) but not who to, because they couldn't strip off the next layer of the onion. Much like Tor.
The following quote from the article highlights the difference between HORNET and Tor:
"Unlike onion routing protocols that use global re-routing through overlay networks (e.g., Tor [23] and I2P [47]), HORNET uses short paths created by the underlying network architecture to reduce la- tency, and is therefore bound by the network’s physical intercon- nection and ISP relationships. This is an unavoidable constraint for onion routing protocols built into the network layer [29, 42]."