I'm largely someone who fits into #1 but I'm the end I'd like grandparents/great aunts/cousins/etc to easily visit my kids digitally, and it would be nice to just be closer to them. I'm not going to radically change my entire digital life to do so, but installing a (hopefully free) app would be nice and something I'd do in an instant.

I think it wouldn't be like >50% of Android users using it or anything, but I imagine there's a lot of people similar to me in this case.