From the ruling of Bartz v. Anthropic:

“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.”

I’m not a lawyer, so it’s possible I’m missing something. But it seems to me like the ruling here implies fair use only holds so long as no net new copies, digital or otherwise, are created. If that’s the case, then it necessitates the destruction of the original.