@asa_2
While interesting, you'd need to add way too many hardware switches to a phone. You could also go with 1 hardware switch for all privacy things, but it would be less useful. Overall, I don't think it works that well.
Still, phones really shouldn't be afraid of using hardware buttons in general.
@asa_2
I remember in the earlier smartphone days, Sony would use rubber plugs on usb port for water resistance. And I've seen something like that in even earlier LG feature phones. Don't remember seeing a sliding door thing on anything.