There is one, one other use for the blink tag. Not that I can think of a good reason to use it, but imagine:
A web browser window that is completely black, save for the following text, in amber, or perhaps, green:
A:\><blink>_</blink>
The cold, painful DOS prompt, long forgotten by so many... set the window to resize to full screen for real fun with those who barely remember what to do at one of these.
But that seems to be about the only use for it. Worth creating a whole new tag? Why not just use an animated .gif?