Yeah, pretty much. It's like a demo of what you'll be using when you install it. It can also be used as a rescue disk. You can also download stuff although I'm not sure how that works tbh.
You don't need an actual cd, all you need is a flashdrive. I have used 2 linux distros and so far, the only tools I needed was google, usb, and computer (internet helps).
When you install this, it downloads the distro you want unto your usb and at the same time it will burn it to the usb. MAKE SURE TO SEND EVERYTHING IN THE USB TO A SAFE PLACE BECAUSE THIS PROCESS DELETES EVERYTHING ON THERE!!!
Find a guide on google and follow it to the letter