However, WhatsApp groups show a name, so that's a workaround if you are using WhatsApp with someone you know well: Make a group for the two of you.
When a friend went to install WhatsApp for their iPad, they succeeded!
Then they said it wasn't working properly. Unfortunately that's because app store search brought up misleading third-party WhatsApp apps for the iPad. If you weren't paying attention, it was too easy to think you were installing the official app from WhatsApp. I didn't notice the app was third-party at first either, and I was very surprised to find no app at all from WhatsApp itself on closer inspection, amidst a page of search resulrs all claiming to be it.
It was actually worse (at least as of a few years ago) because they didn't allow you to manually input phone numbers. You either need the other party to message you first, or use a wa.me deeplink (eg. wa.me/12125551234).
I guess it's debatable whether that's categorized as "it works" :>