Thanks for your response - are you from Apple? I've not seen the phrase "Community Specialist" before. If so, this is the first time I've seen a response from Apple on these forums.
It's disappointing there is no movie functionality for Memories on my Mac. Hence it's not really any different to creating an album or, at best, Photos is predicting what albums I might like to create. In contrast, I find the movies of Memories on my iOS devices a useful addition as it's something I wouldn't otherwise find the time to do.
On your point about syncing Memories between iOS devices, does this mean that if I have iCloud Photo Library activated Memories movies are sync'd but if I don't have ICPL the Memories movies aren't sync'd? (if that's right then presumably I'll have to sync an album from my Mac to my iOS devices and then create the Memories movie locally on each iOS device, which would be a long work round)