Never understood this argument. My parents from a 3rd world country who barely understand English are able to use 3rd party apps like Whatsapp, Duo, Skype just fine. And Duo works directly from your contacts app too (at least in Pixel and Samsung phones), in fact you can see options like "Video call xxx Message XXX with a logo of the apps that support it right in the contacts apps.

Duo came out too late, and Google has a reputation for changing things. Years ago, I tried setting up my family with google’s apps, and they kept changing, and it burned me and wasted my time. So years ago, I switched everyone to Apple, and haven’t wasted any time since.

WhatsApp is really nice, but you need a phone for it, which some of the older grandparents don’t have. But they do have cheap iPads, so everyone uses FaceTime.

I find it astounding that the grandparents have iPads before phones. Most elderly people I know have cheapo Android phones or a few with "accessible" android phones target at people with sight or mobility problems (usually amounts to buttons and a skin with large icons). A few still have older Nokia phones, but these are the ones least likely to have iPads and more likely to have an old Windows 9x/XP computer hanging around for solitaire.

The iPads are usually bought by the adult children to replace the aging computers because they are both much simpler to use and much harder to screw up. I gave my parents an iPad and added them to my plan for $20/month unlimited data. They don’t have to worry about WiFi or anything.

In my family, the grandparents live with their children and grandchildren sometimes, so they don't need phones (or at least only grandma or grandpa needs them, but not both).

But the younger set of grandparents all have their own phones, so it's only the very old that don't.

And then that’s another thing they have to sign into as opposed to just looking in their contacts and choosing the FaceTime icon.

And as far as Duo - only if you have a Samsung phone or Pixel? If you have to buy a new phone anyway - since the entire Android ecosystem is a clusterf* when it comes to upgrades - you might as well get one that is going to be supported for years.