You're in a lucky part of the world. In my area, Whatsapp is used a lot for sharing attachments mainly, e.g sending a photo of a receipt for claiming warranty, contacting government officials, etc. People here do understand that if I say I don't use it, and even though they agree to use SMS and email, it still slightly annoys them as it is out of their norm. I am living by till now without Whatsapp, but it's really difficult.