Pros and cons in everything

USB is more environment friendly and smaller to carry around like it was just mentioned.

Currently Knoppix 9.1 is available and you would put it on DVD

What happens after Knoppix 10.0 comes out? The Knoppix 9.1 DVD becomes obsolete.

And nowadays most laptops do not even have DVD ROM any more.

As was the case here. So I bought a DVD writer which connects to the laptop via USB. I think I've used it once in ~3 years.

On the subject in the question: Yes, you are. But that's ok. We won't hold it against you

dvd or cd is not writable, usb stick on the other hand is, i like more dvd's - cd's than usb sticks bcus it is "static" medium.

for example there is malware that writes itself to usb sticks, that cannot happen with dvd's.

maybe i am just paranoid, but i think it is good in this situation

Something we have not really mentioned is that I trust the liveUSB-writing software less because it's much newer. In fact that probably concerns me considerably more than the physical reliability of the media. I trust the CD-burning software (I use Xfburn but I mean generally) to detect errors and warn me either that the burn failed or that the disc just is no good. (And burning is fairly reliable, now that someone taught me to un-select the Stream Recording option. That was just wasting my blank discs.) I haven't seen much evidence that liveUSB-writing software will report if the USB drive is unreliable and should not be used.

Greetz //////. I have a funny story for you. Over 20 years ago when I was first learning Linux I thought I would be really clever and put /bin, sbin, /usr/bin, and /usr/sbin on a CD and symlink them on hard drive. It worked but didn't reallyu do a thing for security and was a royal PITA. That lasted about 3 days worth until I had a Homer Simpson moment LOL and actually started to learn something about real security. At some point, I can't recall the year but somewhere around Slackware 10, I installed the Nessus suite and got more serious. It's a shame that no longer exists as FOSS. It was an excellent learning tool but O'Reilly wasn't too shabby either.

It is possible to lockdown USB drives. They don't have to be promiscuous

The Live usb offered by slackware's Alien Bob is quite advanced.

I believe programs can be added but most are squashfs isos which are loop mounted and not writable. Getting at the usb is a trick in itself because the system is mounted over it. I have one with wine, into which I installed a library program which updates itself monthly. In my neck of the woods, I haven't once had an attack targeted at linux, as everyone else has windows.

My DVD/Blu-ray drive almost never gets used anymore, as installing, or even just booting a live system from a DVD is just way too painfully slow for me nowadays compared to a USB stick. I couldn't even imagine going back to installing an entire distro from a DVD (let alone a CD) anymore. I can't even remember the last time I actually used a DVD (or a CD) to boot, let alone install an entire distro.

I only use a live system if I'm either installing a distro or my installed distro of choice is broken and fails to boot at all. I don't see any other purpose for live systems beyond things like, recovering files from an unbootable installed system, pentesting, seeing if said distro supports your machine's hardware (which VM's are pretty useless for), and similar.

As for "persistence", if you are going to go to the trouble of setting that up, why not just install said distro (or install a distro that can be actually installed) and be done with it? I personally don't get why you wouldn't apart from the reasons above, as I think the days of "playing around with distros using live CD/DVD's" are long gone in favor of VM's personally. But each to their own, whatever floats your boat...

i have done things like that in the past when i were learning Linux.
i broke my installs roughly 5 times a week lmao.

but it was important to learn to fix things, i also used nessus, in the past.

i have to learn how to lockdown usb sticks. didnt know u could do that.

Okay; but how many attacks are targeted at Linux?

The Crash, Burn, and Recover school is a harsh mistress but the graduates don't "paint by numbers" ..... excepting in hex (

@OP: Reference your post #1.

You're doing stuff in linux, I gather.
Why do you think non writable dvds are the answer?
Presuming you're on dvd, where do you write your data? /dev/null?
Doesn't speed ever concern you? Have you ever considered other forms of medium, e.g regularly backed up hard disks?
Can't you mount your usb drive read only to avoid rewrites?

With linux the dd or cp command is all that is required to create a bootable USB from a hybrid ISO file. It has always worked for me so far...

With Windows some distributions are more particular with one utility or another i.e. Rufus or Etcher etc.

I have not had to write a CD/DVD disk in a long while but I keep it dusted just in case.

Well, I'm using windows xp to view this forum, still have cd's cd RW's, and more than ten floppy disks.

Of course, they aren't much use this year, I thought about discarding my old systems, I could install Linux lite, the older one out there for 32bit hardware, but it would require updating fire fox from version 34 to 52, which I never could do.

I use them for some old games, they are obviously web accessible.

Well, if you really want to live in the past, you can use one of your floppies to install Tomsrtbt which gives you a libc5, 2.0.x kernel and really live in the past.