Because, it is not guaranteed that such information will be safe from future kind of attacks, for example, we all know that quantum computers will be able to defeat ECDSA and use the transactions of public keys to get the private key back without even using any WIF characters, so why make the OP take an unnecessary (even if its theoretically unpractical) risk?
How do you "know" about QC? Did you try understanding all the formulas? I did look into it, and now I really know that quantum computers are destined to utter failure.
Quantum computing is a scam. It will never be able to do anything meaningful, besides generating noise.