No, no, no, no. A killer application is a software package that only work's on a particular machine, so you buy the machine to use it. -So a killer peripherals are equipment that you buy the platform just to be able to use.
Naturally, they will be sold for use on all types of machines, so this definition is blurred: The user will still want to buy them, however, and "ROSE Recommends RISC OS" or something will be stamped on them.
They will be sold across all platforms because they'll work on them, and we'd quite like the money from that.
Note that, until they hit the shelves, no mention will be given of what they actually are. This is just one of the secret necessities that all of us have to put up with, even if it drives us nuts in the meantime.
So why raise the point at all? Well, I like to give a straightforward definition of ROSE, and listing all the sections is the best way of doing that. Even if some of them are blank. And so here we are.