Installation instructions for operating systems inside the VirtualBox virtual machine sometimes suggest that the user select the "Live CD / DVD" checkbox. Other instructions do not mention this flag at all.
What is the purpose of this flag? Does its configuration have any functional differences in the operation of the virtual virtual machine VM?
I can download and install live CDs / DVDs regardless of this checkbox setting, so I'm confused about why it is even there. I could not find a clear link to this parameter in the VirtualBox User Guide (did I miss this?), Leaving me even more puzzled.
Here is a screenshot of the specific item I'm referring to:

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