To copy photos from iOS (and make space for more photos) one connects the device (iPhone or iPad) with a cable to the Mac and opens Photos, then imports.
But with music things "just work" without the user having to do anything. I have "smartlists" set up. When the music (even just play count) changes on my Mac, they sync wirelessly and with no intervention on my part, not even triggering the sync.
Does such a convenience exist for photos? Is there a way to say "iOS: everytime you're on the same WiFi as my Mac, copy the photos over to the Mac, and delete the photos"?
Basically I'm looking for functionality similar to Dropbox/iCloud, but without any cloud or cloud-like features. It seems like a pretty obvious feature to add, especially in a homogeneous ecosystem, and so the question is: are we there yet?
Conclusion
It appears that this problem does not have a solution. bmike
's solution (going through icloud) is the best one can do.