In short, as can be seen by its fruits, the Work of Gurdjieff works for those who can apply it. From what she wrote if I recall correctly, Gurdjieff through Ouspensky was a big part of what, way back, got Laura really thinking, and a big component of what has lead to this community, and especially to the way it works, as well as to the material it is based on - so if (for you to try to determine for yourself) there is validity to the Cassiopaean experiment and to this community, it pretty much follows that there is to Gurdjieff's work, it having played such a large part in forming the former.
fwiw