This article didn't really give any new reasons not to use WhatsApp. All the reasons stated in the article are already known. I thought this article was about a new breach or something, but it's a rehash of info that's been around a while. The article is also a few months old, dating back to April.
If there's one thing I've learned, people will use whatever app they're most comfortable with and whatever app their friends use, regardless of security ("I got nothing to hide!") or features ("I don't care about x or y!"). Then you end up like me, using several different apps. That's not necessarily a bad thing as I like using different apps and seeing how features differ from app to app, like how an app shows link previews, or if it can display a meme by pasting the link in the text box vs having to download the image and attach it in-line. But it's hard to get people to switch when a lot of people don't care.