Bottom-line: the latest claims of ISIS/Islamic State using Bitcoin come without evidence, even though Bitcoin's architecture makes it uniquely easy to provide evidence. The people making the claims are known bullshitters. This doesn't prove that ISIS/Islamic State isn't using Bitcoin, but there's no particular reason to believe that they are.
https://ello.co/zooko/post/4oIyphoYjCmOmnu-HOAOEw
https://ello.co/zooko/post/4oIyphoYjCmOmnu-HOAOEw