It is always good to back up before letting a remote system make changes to your computer. But the way it is supposed to work is that the game checks the cloud storage when you go online, it checks what is newer, your local data or the cloud, then either overwrites the cloud with the newer data, or overwrites your local data with the newer cloud data. So in your case, if the cloud imported properly, when you go online Origin should create the Dwarf saves on your local computer.
However, I have seen so many issues with Steam cloud, and I also don't use multiple computers, so I don't trust any cloud system unless I have to. I would rather copy the data on a flash drive if I am moving back and forth between computers and keep the overwriting in my control.
But type "cloud saves" in the search box at the top of the forums and you will many people have had problems relying on cloud saves. The system may work perfectly, but lost connections or bad Internet connectivity can cause problems outside of the control or you or Origin, so use at your own risk.
