There seem to be so many people there who are burned by using
Bitcoin on Windows...

Here is my idea what could be better:

An image which can be downloaded and installed on an USB memory
stick, just like the Ubuntu installer. But with almost no software except the
Bitcoin client. Everything hardened with SELinux and the like. No use of
swap which could leak keys. Maybe a safe browser if such a thing exists.

One copies the image to an USB stick and boots the computer with
that.  The Bitcoin client is preinstalled and looks automatically for
updates. Before first use, one is asked for another USB stick to which
everything is cloned for a backup.

It could even be sold as a ready-made stick with some amount
pre-loaded, like a pre-paid phone card, administering a
mass market. The receiving address printed on the package, of
course. Perhaps with a pay code for charging with money by a
simple bank transfer. Think in a country with a failing
currency - how would it be most accessible?

It's, of course, overkill for only buying a few post cards in a
web shop. But to store a few hundred bucks safely, this
could be just the right thing to do, and might be a commercial
success.

Any flaws in this ?