You know, I hate flat hand-held electronic devices, especially with touch-screen software. It's like this:
Evolution spent millions of years to evolve the human hand with the amazing ability to clasp objects with an opposable thumb. "Designers" of hand-held devices spent no time utilizing it

. How dumb is that
These are dumb-ass manufacturers - not designers. I have just a basic qualification in ergonomics and these manufactures don't seem to be employing anyone with even basic design sense using principles of human-factors engineering. And they get paid zillions
The hand is designed for clasping, but not flat objects. The thumb can only achieve full mobility when it does not play a part in holding the object.
If bike manufacturers installed flat bar ends, our hands would simply pull off the bars. We can operate our gear shifts only because of the clasp we employ on the bar, which leaves the thumb mobile for independent use. Thus, expect to see a host of tendonitis, RSI, and carpel tunnel syndrome for flat phone / device users. Probably, a new medical term for it will be phrased.