Probably Bittrex try to create "sure trades" and wait for the fish to bite. I mean this is a living proof that we are still at the very beginning of cryptotrading, soon these opportunities will become rare or inexistent, but I am sure right now many still bite, lots of newbies.
That's also what will happen with banks in US offering Bitcoins to their customers, profits guaranteed each time unless the customer is not a noob and can check preev.com in real time.