That just goes to show how we're all very different. I have several thousand photos from decades of travel and I go back and look at them all the time. E.g. I recently looked at my own Notre Dame Cathedral photos after the news of the fire. Yes, there are already million photos of that church but my photos show where in particular I stood, the particular weather that day I was there, my friend with me, etc.
The one trip I forgot my camera was an 8-hour scenic drive in the Pacific Northwest. I had to resort to using the terrible low-resolution camera on a HP PDA. I don't feel "freedom" like Derek Sivers of not having a good camera on that trip; instead I keep regretting the "lost photos" I wish had.
Yes, I get the annoyance with people holding up their smartphones for photos at concerts ruining everyone's experience and the cliche of tourists posing at the Leaning Tower of Pisa. And yes, there's the Japanese joke of "Did you enjoy your trip?" and the tourist responds "I don't know -- I haven't seen my photos yet."
Maybe my preferences for photos to document my trip acts as a crutch for my imperfect memory. I don't post them on Instagram or Facebook. They're just for me.