Font copyright is a weird thing[1]. In the U.S. at least, the letterforms themselves cannot be subject to copyright, but font files themselves as "software" may be. This may differ between jurisdictions (or even be entirely unclear and yet undecided by the courts in some places).

[1] See for a gentle overview in the U.S. e.g. https://practicaltypography.com/the-copyright-status-of-font...

In the article the creator of the font said that they see it as "an echo or a simulacrum", IANAL, but i would say that that recreation is a work of its own under at least copyright law. And ignoring the legal angle for a moment, they did put a lot of work into it, so asking money for it is not wrong imho

According to the article the digital font was created before the recovery of the original letter forms, and seemed to take quite some time. So it's more than just "copy-pasting".

I'm not sure how a lawyer would interpret that, but considering the original font is 120 years old I think it was fine to use it as a basis for something they charge for. From a practical standpoint it would cost me less to just buy it instead of manually recreating it for myself.