If the Book of Mormon was a hoax, wouldn’t Joseph Smith have been able to still translate when Martin Harris swapped out the seer stone?

Edward Stevenson provided an account of an instance in which Martin Harris tested Joseph’s ability to translate the gold plates:

When [Joseph Smith and Martin Harris] became weary, as it was confining work to translate from the plates of gold, they would go down to the river and throw stones into the water for exercise. Martin on one occasion picked up a stone resembling the one with which they were translating, and on resuming their work Martin placed the false stone in the hat. He said that the Prophet looked quietly for a long time, when he raised his head and said: “Martin, what on earth is the matter, all is dark as Egypt.” Martin smiled and the seer discovered that the wrong stone was placed in the hat. When he asked Martin why he had done so he replied, to stop the mouths of fools who had declared that the Prophet knew by heart all that he told him to write, and did not see by the seer stone; when the true stone was placed in the hat, the translation was resumed, as usual.
– The Three Witnesses to the Book of Mormon,” Millennial Star 48 (June 21, 1886): 389–90

Stevenson told this story on three occasions. Why didn’t Joseph make a big deal of this story? Wouldn’t it have given credibility to his prophetic claims?

See:

Evidence Central – Book of Mormon Evidence: Divine Power Required to Translate

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