Why? It isn't like the last Trek series was a hit. And since Netflix is carrying older Trek series...this would help a new one alot. Plus this deal opens the door for CW to take more chance since they want to change up their programming.
"This deal works across multiple levels for us," said Mark Pedowitz, President, The CW. "Not only will we be able to recruit new viewers for our shows through the powerful reach of Netflix, but it also makes The CW an even more attractive option to the creative community."
You also assume because the movie was a success that a TV series would be as well. This deal with Netflix at least gives any new series some hope...Trek or not.