AppleScript that modifies the title of photos to contain their respective date/time. Modifies the photos and videos in-place, directly in the Photos app. Execute with ScriptEditor.

photos-date2title.scpt

(* select at least 1 image in Photos *)
tell application "Photos"
	activate
	set imageSel to (get selection)
	if (imageSel is {}) then
		error "Please select at least one image."
	else
		repeat with i from 1 to count of imageSel
			set next_image to item i of imageSel
			set capture_date to (the date of next_image)
			set short_capture_date_string to the short date string of capture_date
			set capture_time_string to the time string of capture_date
			set new_title to short_capture_date_string & " @" & capture_time_string
			tell next_image
				set the name of next_image to the new_title as text
			end tell
		end repeat
	end if
	return "Adjusted the titles of " & (the length of imageSel) & " photos. The last date is " & ((the date of next_image) as date)
end tell