We have our own example (true story):went to a Barcelona FC match and took some really great pics of Messy scoring 2 beautiful goals. Back in the hotel he found out his phone was stolen. Luckily the pics were already on G+.
If you want to secure your mobile photos, Even if you don't use G+ (yet), Using instant upload is your best choice. Just turn it on in the settings of your Google Plus app on you mobile.
Reshared post from +Tim Moore
The Advantages of Instant Upload