And once the maintained version of Libre Office inevitably drops office97 support you are back at having to find old Libre Office versions and trying to get them to run or port the code.
And that's ignoring the fact that code is a terrible spec. Trying to reverse engineer a file format from a software implementation is a godawful nightmare, and I say that from personal experience.
Given the choice between that and having to figure out how 8-bit ASCII works, it's pretty clear which is the easier problem to solve.