So really, you have no argument, except for a distaste of XHTML. Gotcha.
It seems better to mix that with SVG than HTML5, since SVG happens to also be XML based. Otherwise you have a impedance mismatch leading to some weird corner cases.
my argument is that you might be able to make it work through a lot of effort but you can't actually use it in the real world so it's worse than worthless.
