The original article mentions hybrid but does not say the motors are exclusive to hybrid drives, merely that the motor will be flight tested in a series-hybrid DA36. Besides, the MIT article I linked enumerates the benefits of the hybrid drive. The word 'hybrid' is in the subtitle. I suspect Siemens is focusing on hybrid tech at the moment because battery tech is such a moving target and they want to use an existing airframe. Ultimately, I think all-electric aircraft will find their market in short-flight urban transport applications where noise, pollution, and reliability are huge factors.