It's more of an accounting ploy, after sale to a newly created special-purpose vehicle company Amazon will be leasing the GPUs back to themselves.

Also probably works as some risk mitigation if the chips become quikcly outdated - it will be on another company's balance sheets.

These are my very quick takes, FT article still isn't available on archive.is, but this has some insight from it: https://dealroom.co/news/other-1ltaeys-amazon-seeks-to-offlo...