This is a theme I've visited a few times in the past, here, for instance or here. The label "social media" will turn up a bunch more.
Time was, pictures had weight. Paintings, of course, were for posterity. They were for the unending future, for tomorrow but also for future generations, a permanent object. Photographs, on film, were also for the future. A instant was frozen, so we'd have that to look at next year, ten years hence, or when we were old. We took pictures of the kids so we'd have those moments in the future, and so our kids would have those moments to look back on when they were grown.
Pressing the shutter button cost something. A few cents for film, a few cents for processing, a few cents for a print. A factor at least as important and perhap moreso: the print bore the weight of permanence, of time. Susan Sontag remarked, glibly, that we did not photograph important moments, but that moments became important because they were photographed. While there's some truth to that, there was still a minimum bar of inherent importance the moment had to pass. We did not photograph our lunch, our coffee, that guy's hat. At least, not very much. There's a burden imposed on us when we commit some scene, some viewed object, to the permanent record, and we felt that as much as we felt the literal cost of film and print.
I've said most of this before.
With the idea of "use" in hand, though, we can push a little further. In past times, especially in the era of film, the "use" for a picture was almost always tied up in permanence. We made pictures because we wanted to use them, in some long-term way. The idea of taking a picture so that we should show a picture of a thing to our friends, and then throw the picture out, was absurd. Photographs might not be oil paintings, but they were certainly not so lightweight that we'd use them once and then discard them.
Besides, with the delays inherent in processing and printing, it would have been far too tedious.
Now, taking a picture is free. Sharing it is frictionless and instantaneous. And as a consequence, we are freed from the weight of time and of permanence. Photographs are free to be ephemera. They are an extension of our sight, we share a photograph thoughtlessly, trivially, not as an object in its own right, but as glimpse at the underlying thing. When a photograph is weightless and frictionless, the "use" can be anything at all, however trivial.
Mike, over on ToP, asks if we're in the middle of a new fad for photography. I think we're in the middle of something much bigger and more important, a sea change in the way we relate to photographs. Photographs are weightless and frictionless now. They float, they move, the appear and vanish. We are OK with that. This younger generations treat that as normal.
As artists, we seem to lean toward making things with weight. This probably explains, to a degree, the minor trend toward film, wet plate, and other permanent methods. It's a backlash against that weightlessness and ephemerality. The artists seeks to distinguish his work from the ephemera, to distinguish his work as permanent, as massy, as not trivial.
Here's a closing thought for the day: Why? If modern art has taught us nothing else, it has taught us that art need not be permanent. Ephemeral is OK. Tino Seghal, Banksy, many others. What can you make of that, in your own work?