Special Forces (Golden Rainbow)

I have another, topic up but considering this question is completely different I decided maybe it should have it's own topic, if that is ok.

I am confused about special forces, I have several special forces units, and I don't know what or how to use them. I've had a spec ops force go against a fotress and its defenses they didn't die, but it did nothing, told me that the weapons were ineffective. I'm not sure what to do here and how to use them, can somebody please help me

Drop them in a country you are at war with and they can be moved around to do the 'painting', occupying land. For a C3 war you dont really need them as your land forces for blowing up things will do the same thing.
For a person v person war, loads of them dropped in your country can be a pain. It takes a lot of valuable time to destroy them one by one. I've never used them to attack things, I would imagine the only time you would, would be one against ones, SF v SF. And I suppose they could be used for temporary blocking invading land units, but they wouldn't last long.