What is the purpose or intention of the "Live CD/DVD" checkbox in a VirtualBox VM's Machine Settings Storage screen?

Instructions for installing operating systems inside a VirtualBox virtual machine sometimes advise that the user ensures that the "Live CD/DVD" checkbox is checked. Other instructions don't mention this checkbox at all.

What is the purpose of this checkbox? Does its setting have any functional difference in the operation of a VirtualBox VM?

I am able to boot and install live CDs/DVDs regardless of this checkbox's setting, so I'm confused about why it's even there. I could not find a clear reference to this setting in the VirtualBox User Manual either (did I miss it?), leaving me further perplexed.

Here is a screenshot of the specific item I'm referencing: