Really annoyed by the aggressiveness of photo library optimisation. I have it disabled, because as others have found it, would offload photos far too quickly with seemingly no intelligence. It should keep more of the recently created and view photos downloaded.
Either be intelligent or be more customisable.
I have a 64gb device and 5gb left. To me that's ok, but fair enough if Apple think I should free up a bit more space. So they keep suggesting to optimise photos. I have 28.4gb photos. They say I would save 27.33gb if I optimised. That means they would only leave about 1gb of photos on my device. It's feasible that that 1gb is the low resolution of every photo - in other words, they would offload the full resolution version of every photo. In any case, it doesn't seem like it would leave a lot of full resolution versions on my device.
Why optimise so aggressively? The 27.33gb of free space it would create in addition to the 5gb I already have is a waste of storage. Over 30gb doing nothing. Some of that could be filled with photos. Much more intelligent algorithms could be used. I do view older photos and videos quite regularly. In this particular example, why wouldn't only offloading, say 5gb of the oldest and least viewed photos be adequate? It would leave 10gb free on my device - 15% - which is fine.