> one of the reasons WhatsApp has done so well is that they basically supported every platform under the sun

Not really. There's still no iPad version.

My friend installed Whatsapp from the App Store for their iPad, to find it didn't behave quite as expected, and didn't match their phone and desktop experience.

That turned out to be because it was an app from some random third party with its own features. It used Whatsapp in the name, and had a similar logo.

When my friend realised they were unexpectedly using a third party app, from a provider they'd never heard of, they were worried they'd accidentally given away access to their account full of sensitive messages to someone they didn't trust.

I was surprised my cautious friend would install the wrong app by mistake, as the Apple app store is normally good for well known services.

While scrolling through Whatsapp apps, it took me a while to realise the top search result, which my friend had installed, wasn't actually from Whatsapp (but looked similar). Even though the logo was a little different, I assumed that was just a quirk. It's just so unexpected to find that what you get on iPad isn't the real thing, when searching for Whatsapp gets you the real thing if you're looking from an iPad or Mac.