Many of the evidences for the Book of Mormon would be much easier to explain away if Joseph had written the book in his own time rather than dictating it.
In addition to all the witness accounts which confirmed that Joseph dictated the text, there is also evidence from the manuscript itself. Most of the errors in the original manuscript are based on the scribe mishearing what Joseph was saying. For example 1 Nephi 13:29 says:
because of these things which are taken away out of the gospel of the Lamb, an exceedingly great many do stumble
In the original manuscript the word “an” was written as “&”.
Is there any doubt remaining that Joseph dictated the book? Why would Joseph choose this difficult method if he was orchestrating a fraud?