[chud]

I happen to have a second copy of the private key on my phone at this moment.

I've always heard that you shouldn't keep a private key on your phone...

[palmer]

That's correct. A private key on a phone is vulnerable to someone who hacks the phone. Furthermore as Drago pointed out the private key can simply disappear or you can drop the phone in the lake. But my private key on my phone is a duplicate of the private key on the paper wallet in my safe. So I don't have to worry about the loss scenario, just the theft scenario.