Now this tech in some crazy hands is dangerous.
But with the power amplification in modern times -
Two generations ago - a person could create a small business or small terrorist act alone.
10 years ago it was possible to have a thousand person billion dollar company and 9/11 ...
Now we have a billion dollar company with single digit numbers of employees and we will have the first billion dollar one man company in the next 5-10 years.
I leave the rest to your imagination. But you should not be worried from terrorist organisations - disgruntled lone wolves will be the real danger.