That's right.

Nowadays many linux CDs/DVDs/USB sticks start by booting into a live system, and then offer you to install it.

Back in the days when Knoppix was popular, the major distros only had normal installers, so you needed a free partition for installation (or resize an existing windows partition to make room, which was very risky).

As a 9 year old in late 2000, Knoppix was my introduction to Linux. I wasn't asked to install Linux on the family computer (not that I knew how to).

I don't remember how I first heard about Linux or Knoppix but I do remember those first magical moments using it. While I've had many influences Knoppix definitely was an early influence on my tech interests because it was so easy to start.

A worthy present-day update this way of lowering the barrier of entry would be a convenient, pre-configured way of running the same persistent set of configuration state and user home from either a boot media start or within a virtualized environment. Virtual container with optional full reboot. Does something like this exist?

There is also a games version with quite a few games.

Also, the internet

Reading these comments I feel obliged to mention the Android app 'DriveDroid' which lets you store multiple disk images on your phone and then acts as a bootable USB disk. I've got GParted, CloneZilla, Alpine, Debian etc live disks always in my pocket. All I need is a micro-usb cable (which most modern homes seem to have laying around) to boot into various OSs and tools.

No affiliation, I just think it's a cool free app and it's proven very handy for me loads of times.