If the core value proposition of a piece of software, that it's marketed for, is automatic photo organization, it kind of defeats to purpose to have to configure something to make it do what you want. Most people don't want to configure software, they want it to make their lives easier out of the box as much as possible.

If the only thing you care about is backup, Dropbox and other services offer that (e.g. Keepsafe). I use Google Photos because of peace of mind. I know I never have to worry about losing photos, and when I need to find them, it's easy. I've got like 20 years of photos backup. Just yesterday, I wanted to show someone a picture of my daughter from a trip we took in 2012, and I found it in about 5 seconds. When I take photos of my kids, they are automatically shared with my wife, instead of having to constantly manually be asked for them, and manually select them. I focus on just taking pictures and spending time with my kids, I never worry about photo backup, or photo organizing anymore.

It seems you also use it mainly for backup?

Would you still use it if the grouping feature didn't save pictures it could not confidently group?

I mean, at some point you take the first photo of your kid. If it threw that away, then when you take the second photo, there's nothing to group with and it throws that away too.

Pretty useless if it throws away singleton sets.