This is basically as far as they are willing to take it with photos it seems--they see the usability of being able to exclude certain ones from the main album so that when people are showing their camera roll or giving another app access to it the hidden photos won't show up as part of it, but seems like they don't want to treat them as actually protected in the sense of being behind authentication of some sort. Whether its because they don't see them as something that stores private data (like notes, for example), or some other reason, or perhaps no reason. Hopefully that might change in the future, as it did with Notes, or it might not, kind of like the large volume control overlay that still there despite pretty much universal understanding that there are better ways of going about it.
that’s what I meant.