Apple seems to be lightyears behind Google, you can't even work at the same time in the cloud on a document, if you do so it will save after doing so two seperate documents.
My girlfried shared a document with me, i opened it by clicking on that e-mail link (by the way, I have to use all the time this e-mail link, it never showed up as an icon in my iCloud) we both had it open at the same time and we both changed a cell at the same time, she got then a conflict message and could save either mine or her or both documents, she saved both, at the master document her changes where saves at the copy my changes where saves,
after closing and reopening at my side,
my changes where gone, they where saved at the new copy, but as the new copy was a new doc it was not shared with me ... so I never saw my changes again.
this is all a little strange if you have worked for so many years with Google and got presented from Apple, we now have the same posibilitis to share, it's not even close to how it should work ...
I would not name it Beta, it's more an Alpha state.