(PS: I do own Cloantos Amiga Forever which I bough a few years ago and have had no use for it, not even the ROM images and why do they encode the ROM images on their CDs ")
I can't say exactley why Cloanto encodes the ROM images, but my guess is that it was done to appease someone who claimed to own rights to the ROMs.
It might be worth asking Cloanto, who knows, they might answer.