Oh luckly I'm not mad! The estimation is only with the --vanity flag, with --vanity-n you get:

Benchmarking of cores disabled for vanity npub key upon proper calculation.

I think will not be used.

Here my speculation about the security implications: @note153acau3skqad8hlmn6qufkh80wuzz8e4n7jp05a50xnxyqnvw6ls4wxcz6