No, its the opposite, the Schlumpf exists since much longer than Efneo and is sold by many bicycle shops.

Now, personally, I wouldn't use any of both on the Birdy, the 9-32 or 9-34 cassette solution is much better, it has a better efficiency and weight less (FYI., I have a Schlumpf High Speed Drive on another bike).

For Helix, there is also a big question-mark about what will happen now that they announced that they won't be able to provide the many remaining Kickstarter and pre-ordered bikes and if they have to refund many backers and pre-orders that do not want to add money to buy an Helix at the full price