My example would be: One single keyboard shortcut is the quickest and easiest way to place a copy of your file somewhere and directly continue working while the old file is automatically closed, since you usually don't need it anymore.
That's basically what you achieve with Duplicate, isn't it? Because you can totally set up a keyboard shortcut for that. Sure, in some cases it would be more convenient to "save as" or "save a copy", so adding more alternative ways of doing this would be helpful for sure. Though I don't think Apple will do that - to them, I speculate, the old way was Save As and the new way is Duplicate.
I work with complex documents in Numbers and I frequently have to try some "what if this or that" (similar to the creatives with image editing). Sure there are workarounds like clicking the top bar menu or duplicating the file in advance. But all of that isn't the way of simplifying or getting the computer out of the way. It's just the opposite. Too much sacrifice for a tiny bit of security.
In my view, that's exactly what Versions shines at. You can try out things, keep them if you like them and revert them if you don't. You can even keep a version with the changes in case you'll like them later. Or if you know in advance that you're not gonna keep them, again, you can duplicate - it can essentially be used as "don't save this", just with the annoyance of having an additional window floating around that you won't need.