Why am I not able to access all of OneDrive Files?

Is it just me or the Windows10 new OneDrive synch option is terrible and very unintuitive. They have removed the placeholders that we have in Windows 8.1, but now want us to Synch/download all of our files to the computer in order for us to be able to use it. Not to mention, it is makes ZERO sense. How do they expect us to download/synch 1 TB of OneDrive files on a 250 GB computer? What is the point of Cloud then?

Lastly, how to do you undo the selected folders Sync to all folder Synch??

there should be a setting which makes OneDrive offline only. But yes, I agree that "offline only" should be enabled by default.

It's an incomplete feature. There is supposed to be a new OneDrive app later this year. The windows 10 store doesn't even have a OneDrive app.