Comment # 6 on bug 1209923 from Stefan Hundhammer

Well, the YaST partitioner starts with a stern warning that you should only use
it if you know very well what you are doing. The reasoning for that is not that
we consider our users to be stupid, but that we know that this is a tool that
is perfectly capable of letting you shoot yourself in the foot.

It's powerful and flexible; it operates on a very low system level. And that
gives plenty of potential to do damage as well as to fix things in very
pathological situations. That goes both ways.

So, maybe you intentionally got your USB stick (or more general: disk) into a
state that is not 100% consistent; like in your dd'ing an ISO scenario. Maybe
in that situation, you still need to so some tweaking to make the installation
work for you; your BIOS may be a bit quirky and need some more customizing on
that stick to make it boot. We don't know. And we don't want to impose more
restrictions upon you than absolutely necessary to use the tool.

The moment we introduce even more checks and restrictions, somebody will
complain bitterly that we made his special use case impossible.

If anything is missing here, it might be that piece of documentation that tells
users how to restore their USB stick for general use after they no longer need
the installation ISO on it.