From a miner's perspective, I don't see how 1 block per second is possible: It takes at least 1-2 second to re-initialize the miner and get new work from the network, if new blocks arrive every second, it means the miner would never get ready for the real calculation to take place 
Yep most hardware in use for mining has second to multisecond latencies, not even getting into the latencies of global propagation in a network of decentralized volunteers (rather than trivially coerced corporate interests).But I think if you fixate on one second you're not getting the value of of the paper. Just multiply their numbers by 10 if you find 1 second is a bit outrageous considering the practicalities that their analysis excluded.