Float in footnotes

Float in footnotes

The question about adding footnotes in floats or captions of these has been asked and debated often.
What is about floats in footnotes?
I can't seem to get a floating figure environment within a footnote. Here is an example:
\documentclass[
DIV10,
a4paper,
pagesize,
english,
]{scrartcl} %scrreprt, scrartcl
\usepackage[english]{babel}
\usepackage[utf8]{inputenc}
\usepackage{blindtext}
\usepackage[demo]{graphicx}

\begin{document}

\section{``Floating'' figure in a footnote}

\blindtext\footnote{ %
\begin{figure}[htbp] %
\centering %
\includegraphics[width=0.5\textwidth]{demo}\caption{\dots and a caption} %
\label{fig:demo} %
\end{figure}} %
\par
\blindtext

\end{document}
Further is it typographically accepted to have a graphic in a footnote, if the only the text in the footnote refers to this figure? Nothing else in the whole document.