typing biometric software has been around for a long time (biorhythm) and from what I remember from years ago had issues with users typing in from different devices all the time, laptop to ext keyboard, iphone to ipad with keyboard, kiosk, etc... I don't think it would be more secure or as you put it "much more secure" than say, user/pass and a push notification as the push notification is out of band. These used to be called 1.5 factor as it wasn't quite 2 factor.
I understand your opinion, and yes, it's hard to be able to identify the owner of an accountby checking smartphones, tablets and desktop keyboards. The recommendation is to create separate signatures for all of these devices, in this way the typing signature will be more stronger and the keystrokes verification will be more accurate.
We are adding new cases to our algorithm almost weekly, the typing detection keeps getting better.
