I can't speak for the person you replied to, but I rely on a product to "store" pictures so I can access them when I'm not at my main computer. I'd like to show them to others using my phone, share them with other computers (like my wife's) so she can edit some, or add to the collections, and they are also accessible to the machines hosting my web sites, so that others can browse the ones I choose to publish.
Encrypted backups are great for recovery, but they don't address many other useful features of these additional products.
I use Lightroom, but it's fairly "dumb" in its approach to photo management: no features, no surfacing of old content, just a useless grid. GPhotos on the other hand surfaces old photos in interesting ways, shows you moments from the past and even sometimes creates cool edits on its own. It's actually pretty magic, and feels years ahead of Lightroom.
Well, they're also for different use cases, so I don't think "ahead" is the right word. Lightroom is pro-oriented and assumes that you know what photo you want to find, whereas consumer photo apps are more about browsing and availability than anything else (hence the autogenerated montages and cloud storage integration). But that is exactly why I use a combination of Lightroom and Apple Photos. (edit: Though I wouldn't mind having some of these slick organization/discovery features in Lightroom as long as they didn't ruin the rest of the experience.)
