What I think he means is that a mobile phone is a portable mass-market consumer device that you would reasonably expect to see a lot of harsh environments. My mobile goes with me to a lot of places where my tablet does not - I live near a beach and frequently have to put my mobile in the same pocket as some keys (due to lack of pockets in my trousers) whilst in a sandy environment.

It is not unreasonable to expect such a device to be ruggedised by - for instance - having a good scratch-resistant coating. I don't expect it to be unblemished, but I do expect a device to take fair wear and tear without becoming unusable.