Formatting not applied to struckthrough text

Like it says on the tin, if you strikethrough text (with ~~), formatting isn't applied. Instead the formatting marks are shown. As an example:

So this is strikethrough text. Here I've tried to italicize it, but it just shows up with asterisks instead. Now bold.

I don't know if it's a feature or a bug though. I guess that's your call. :)