[mikepurvis]

That's fine, though. Building it takes time and money (people, materials, whatever). You're going to have to explain your idea to your investors in order to raise capital. During that process, you need to be protected from them taking your idea and starting a separate business behind your back.

Lots of patents really are just ideas for things which might work rather than things known/proven to work. Possibly these should be differentiated somehow, and maybe have a shorter time horizon on expiry if they're not "upgraded" from an idea patent to a working-device patent. But that's a legit reason for idea patents to exist, and that's the present reality.