Google+ is used to backup up your photos. If you have a different way to do that you can disable it with no problems. In some phones running kitkat the Photos app is part of G+ so, if that's your case, you'll need to use another gallery app.
I don't backup photos OTA or over WiFi, I use my PC via USB connection, so that's not a problem.
I'll try delete or disable and see if any effect.
I can always re-install or re-enable if there is a problem.