You never know one day (if you really bad luck until don't have road) if your phone accidentally drop inside the water or any faulty of your devices that cause cannot turn on your device, then you will understand why I need additional memory card.

You might feedback to me nowadays everybody can use Google Drive or Dropbox that can backup all your files to the cloud anytimes. But sometimes some of the confidential documents, we won't put the files to the cloud server coz everything been monitor through the cloud storage service provider.