Why don't all mobos have something like Asus's usb flash

I was looking at mobos and saw usb flash back on a asus mobo and was thinking "why the hell don't all mobos have this?!". http://event.asus.com/2012/mb/USB_BIOS_Flashback_GUIDE/ You don't need RAM, CPU, or anything except a psu to flash your bios. 

Does this actually work or is it just something to drive sales?

not a bad idea. i'm not sure about other. I know asrock allows you to flash the bios over internet, but I think you need a cpu and all that installed 1st.

Yeah but I like no cpu needed incase you have an old mobo and buy one with a new fx chip.

exactly what I was thinking

I know Gigabyte also lets you flash over the Internet, but this isnt in all of ASUS's Boards correct ?

Most new ones I beleave.