Hi jazzbiker
... It is so comfortable and convenient to: ...
That's an easy statement to make when you have years of
experience and hindsight to rely on.
About 15 years ago when I was looking for an alternative to
Windows, I had neither of those to rely on.
... 1. dd it to some drive and instantly dive at the full depth. ...
I didn't know about dd. As a newb, that was probably a good thing.
... 2. Run it in qemu, perform some tweaking and return to the point 1. ...
Even if I knew about qemu, my hardware probably was not
up to the task of running it.
... 3. Mount in rw mode and adjust manually. ...
Mount? That would have been a foreign concept for someone coming
from the Windows world.
Back then, I started out with zero Linux experience. I wasn't looking to
install anything. I didn't want anything writing to my hard drive.
Those live ISO's were a useful stepping stone for this know-nothing
newbie. They allowed me (with my limited knowledge) to test various
distros to see which ones were best suited for my hardware prior to
committing to installing one.