The real reason was at the end. Did you catch that sentance? "Digital rights management and security designers also have an interest in EFI because it gives them a new level of control over the hardware." There is nothing wrong with the current BIOS scheme. What they are talking about won't really "kill BIOS", it will be the new BIOS. Put simply, the programs need to be able to talk to the hardware. Given the diversity of hardware that might be on a motherboard, you need interface code that is fixed to the board so that the programs can access the hardware without knowing exactly what it is. This is what we call BIOS.

And what's this about stealing my hard drive space?

This is the worst idea ever.