i see your points. but the album in photo app, same as that in google photo, is more kind of tagging than the old-school folder concept. hence, a photo would belong to multiple album (or tagging), while photos in folders are kind of exclusive, like a paper which could only be physically stored in one folder.It would be nice to have an option to sync but also be able to delete from the phone. I ended up exporting certain albums to my hard drive and removing from Photos entirely.
No it's a very useful feature. The trouble with "you can add them to an album and no error would be caused" is it gives you no indication of how far back you need to go to find unsorted photos. For example, I have a toddler, which means I have a ton of photos of my toddler. I also have an album for him, going back to when he was born. I don't update the album daily, so whenever I want to make sure it's up to date I have to go into that album, see the date on the last photo, then go to camera roll and scroll through a billion photos to find it, and then select all the subsequent ones. Conversely, "show me all the unsorted photos" makes it a very quick and very easy task.
This is one of those things, much like "show emails by sender", that the Mac has and there is no zero reason that the iPhone doesn't have it — and certainly no reason for an iPad Pro to not have it.
any reason for you insisting to sort photos into albums?
with the face recognition, you may search for a person any time, and you may also assign multiple faces to one person.
as a workaround, you could search for the subjects of unsorted photos and add them to your named albums.