There are so many alternative communication systems besides Whatsapp and Facebook owned systems. Had I not checked HN and other news sources, I wouldn't have even noticed Facebook was down. I communicate domestically and internationally. I use LINE for international communications but there are plenty of additional options.
At certain age and health conditions, the only viable communication media you have left are voice and/or visual.
and you can't use your voice on phone if whatsapp is down?
If you're in another country, this can be expensive.
How about people who don't live in their home country?