I can think of only 2 reasons she would dlestroy all of her research:
1. She didn’t want anyone else to profit by using it.
2. She was not confident in the accuracy and claims of her own research.
Either way, it is a great loss to history for her to have done that, unless her papers were bogus.
3) She did not want her work to be used to publish a book and wind up as a ‘footnote’ with someone else taking credit for her hard work — which happens far too often to live authors, let alone dead ones.