Commenter Crow asked me for my view on the subject of The Holy Grail - and his question was interesting to me, because I found it hard to give a brief answer.
In one sense I am not very interested by the HG, because I have very seldom thought about it spontaneously. In another sense, I have read quite a few books which feature the topic, and it is bound-up with something which does interest me intensely, a secret mania - perhaps, which is the idea of Jesus visiting Britain during his life and before his ministry, and the linked idea that Joseph of Arimathea came to Britain not long after the crucifixion, and founded The Church (probably in Glastonbury).
So - the actual object of The Grail is not a thing I think much about, but the circumstances by which it arrived in Britain is. If pressed, I would say that I sort-of, mildly believe that the object was real and came to Britain; that it was precious and formed the centre of perhaps the founding church in England; but not that it had any magical powers - especially not of a kind which could be used for evil purposes.