[_JamesA_]

That's probably because phones and tablets usually have oleophobic[1] surfaces.

[1]: https://en.wikipedia.org/wiki/Lipophobicity

[anexprogrammer]

I seem to have oleophobic-proof fingerprints then. I'm constantly cleaning phone screen (swipe on jeans these days now phone is not spanking-new).

You could easily see my swipe or pin pattern from prints and smudges, even from one use, which never happened with actual keys.

[newscracker]

The oleophobic coating does vanish with use over a period of time. That's why you wouldn't see fingerprints and such on a new device, but would on an older and well used one.

[criddell]

My phone screen is smudged, but it doesn't really bother me. If I spot something on my monitor, I can't get any work done until I have it cleaned off.