You quote the degenerate case of sync, where you have one device with a file and you want it on another immediately
Not immediately after putting it on one device. But immediately before (say) watching the movie.
Further more you compound the stupidity of your blow by blow comparison, you've entirely left off tha fact that in the equivalent scenario you have to remove the back of each of the two Android devices, and take the SD_card out of one and put it in the other.
No, SD card is mostly part of the same device. Just that you get much bigger storage capacity than without SD card. For which capacity one would need to use iCloud in the degenerate case on some SD-card-less devices.
But the degenerate case is not what defines what a thing is.
Just FYI, this is not a "define iCloud" shill training session going on. No one attempted to "define" iCloud here.
So far you were maintaining there is no download happening. Now when that didn't work, this becomes a "degenerate" case? This is the topic of this discussion, whether degenerate or not. Go to some other thread which has the topic "define iCloud".
And in the normal case happens without you noticing. Because it happens without you needing to ask for the download. The sync service has already done it for you.
Thank god it has decided which movie I want to watch. The choice might have killed me.
None of this happens in with SD-cards.
Yes, store the movie when you have it, watch the movie when you want to.
Yes, other than the topic being discussed, your post is applicable to everything else.