iCloud Drive advice needed

in addition to Dropbox, today I wanted to upload some files from my MBP to iCloud. Since I have never used iCloud, I accessed it in the System Prefs, logged in, upgraded to iCloud Drive, and, as a test, I copied (option-dropped) a file from the desktop into it. Then I removed it.
Then I did what I usually do with Dropbox, i.e. I clicked Sign Off, and I got this message:
“If you turn off iCloud Drive, all documents stored in iCloud will be deleted from this Mac.
Your docs will still be available on other devices using iCloud.”
Since there was nothing stored, I clicked “Delete from Mac”.

So my question is: is iCloud Drive supposed to stay always ON? In such case, what happens when I shut down my machine?
By the way, I’m not concerned with other devices (iPhone etc.) since I do not have any of them. Nor am I interested in backing up Apple apps docs. I’d like to use it only for what I decide to upload.

Any related advice (short cuts etc.) welcome. Thanks.

Sorry for the double post…

About the iCloud drive check this bellow…
And this is the Automatic status of synchronize from Apple
Is iCloud working on Apple’s side?

From what I understand from those docs and from iCloud Help, I guess iCloud Drive is not the right tool for me to keep manual backups: i.e. I want myself to decide when to replace data, as I do adding/removing files to/from the Dropbox folder and accessing and quitting Dropbox.

iCloud is to use most for sync iPad,iPhone with your Mac.(That mean iCloud always ON)
iCloud is most popular like exchange method like documents,photos.
For my opinion is NO recommended as alternate to Dropbox.
Best will be the google drive.
Read for the google drive api here
Google drive api

Thank you, Loannis.

I think iCloud drive is always on, it’s a folder on your hard disk that syncs when it can.

Check out:
/Users/*/Library/Mobile Documents/com~apple~CloudDocs/

It’s not the Apple approved way of accessing iCloud documents, that would be 100x harder! With APIs and code signing profiles and requesting permission from Cupertino.

actually I intended to use it as a storage to be accessed when needed, as I do with Dropbox.
But now I see that it would not satisfy my needs.

As an iCloud Drive users, I can share some advice about using guide. There are 3 parts which I want to share. A guide which I recommended as below.
Part 1. How to Set up iCloud Drive on iPad
Part 2. How to Use iCloud Drive on iPad
Part 3. How to Access iCloud Drive