Technically, yes, but as I mentioned in my initial post, I rarely use the PS4 in the other room myself, however, I failed to mention that it does get regular use by family members when they come over. Like I said, not really a huge deal (especially as I have a 2TB drive in that other PS4 that isn't filled yet), but, it means I will have to download everything twice if I want to play something on both PS4s. Or, I could get a second external, download everything to that AGAIN, and then if there was one game I had downloaded on my main PS4, I could bring the drive out to the living room and use it temporarily. At Sony's glacial pace when it comes to this stuff, I doubt it will be changed anytime soon, which is a bummer.
Right, it doesn't let you use it at all. I didn't even think about the indexing issue, as both PS4's are mine, so I don't really care, but that would be annoying for those items to be left behind if a friend brought a drive over with a bunch of stuff only he owned. Again, not a huge deal for me, but I wish these kinds of scenarios were thought of by Sony a bit more before they implemented the feature, because now we're going to get months and months of people wanting it changed (and I think rightfully so, honestly). It seems Sony tends make changes based on literal requests, without thinking of the bigger picture, haha.