facetime doesn't show enabled in contacts on iPad (does on iPhone and Mac)

I created a new contact, on my Mac (Sonoma 14.6.1), with both phone number and email address, and the facetime button is shown in wonderful blue. In contacts on the iPhone (iOS 17.6.1) I see the same information. On my iPad (iOS 17.6.1) however, the facetime button is in grey. I tried to create the same contact on the iPad, but the result is the same: grey on iPad, blue on Mac and iPhone. On all 3 I'm logged in through the same apple ID, and the settings for iCloud are identical on all devices.