IANAL, I can only cite court decision: "And, the digitization of the books purchased in print form by Anthropic was also a fair use but not for the same reason as applies to the training copies. Instead, it was a fair use because all Anthropic did was replace the print copies it had purchased for its central library with more convenient space-saving and searchable digital copies for its central library — without adding new copies, creating new works, or redistributing existing copies."

You don't have to burn the book, but then you can't scan it, either.

In some places there's an exception to copyright law for format shifting if you destroy the original. If you don't destroy the original, then you made a copy and that's not allowed.