It's not really amazing. Windows is controlled by the registry, so by
changing the registry, you're changing the way windows works. No
biggie, but you do need to be careful, as (just like in a relational
database) everything is tied to everything else, so making one little
tiny change can have big effects! (In other words, always be really,
really, *REALLY* careful when you're messing around in the registry.
You can, as many people can testify to, wind up with a system that
isn't usable anymore. (Reformat, and re-install *everything*)
As for the purpose... In theory, you're supposed to be able to have a
clipboard that has multiple clips in it that you can copy and paste
from as you need/want. There used to be several dozen programs that
did this outside of any windows product. I would guess that someone
at MS rather liked the feature and figured everyone else in the world
was just like they were and so it the feature got in. Indeed I know
some people who *do* enjoy that feature. More people I know, dislike
it, and (like you) wonder why it's there, and how to get rid of the
"silly little pop up they can't get rid of" (usually muttered with
angry overtones....)