Are there any devices which have the ability to scroll by means of the sensor side (where we usually have the thumb is in the vertical grip) and if not, maybe there is an objective reason?
The landscape grip, the thumb also rests and moves freely along the body.
If the motion of the thumb along the body to make scrolling less occlude screen contents, and less muddy.
Upd.: here found a similar idea, using gestures on the sensor of the fingerprint on the back of the phone.
But it is not configured for smooth scrolling of pages. Possible because the device of the sensor.
The location of the sensor on the back is convenient with the vertical grip, but horizontal is not. So the question remains.
Upd2: here's a similar question is it possible to use the fingerprint scanner on the side to scroll in Sony.
One of the respondents, tried using the program to hang opening the message center on the sensor, but there were a lot of false positives.
But if you want you could make this function disable, and configure the software properly. And besides touching the sensor will often false trigger than keeping your finger along it. Too cool looks like a thing to that it is not technically feasible to implement. Maybe there are other reasons.
In Android Oreo opened up the possibility for third-party applications to use the sensor of the fingerprint for recognition of gestures. It is safe, so API means that the gesture recognition on the Senor is only possible if the sensor is not used to authenticate at the moment.