In some countries, cellular companies still charge for sending text messages to people who have a different provider. WhatsApp is an easy way to connect with all of the people you know without paying extra fees.
And there’s a whole customer interface that lets you order directly from small businesses, which is super convenient if you live in a country that still has a lot of “mom and pop” stores instead of giant superstore chains.
For me, everything that happens on HBO after Jon is stabbed by his brothers is just high-end fanfic. I will always believe that the showrunners fucked up the ending. And, let’s be real, GRRM isn’t going to prove me wrong.