Why bother having an architect of the Capitol, then? Why bother building government buildings out of stone when wood is cheaper? Appearances matter: would you want to do your taxes with Comic Sans?
These have existed well before someone said "let's create Public Sans!". It would be nice to know what the reasoning was. The Github page only goes into the details of how Public Sans is different from Libre Franklin.
As a taxpayer I personally am pleased that this is at least one place the government isn't subsidizing some corporation for private gain at my expense. Even if a foundry licensed the font to the government for free, it would be free advertising for that entity. This is one area where I think it makes excellent sense for the government to have done something on its own. The surprise is that it actually looks decent.
Many (most?) of those typefaces are commercially licensed, and can't serve as a universal "default" for typography across all the USG's web properties. Additionally: almost none of them are in OS/browser font stacks, so using them would incur logistical problems in addition to licensing.
There are two problems with that reasoning. First: it is clearly contradicted by the inclusion of Source Sans Pro and Merriweather, both licensed under the SIL OFL and developed by third parties, in the USWDS list of components. Second: creating another font that isn't in operating systems and WWW browsers does not solve the latter problem.
Switching to Public Sans solves none of the problems you're pointing out.
According to the Public Sans's Github page, "Source Sans Pro" was the USWDS default, which is a SIL font (so no licensing issues) and is also not in the OS/browser font stack.
I don't understand your second point. Public Sans isn't in OS/browser font stacks, either. What makes its inclusion more likely than, say, a 15 year-old open source font like DejaVu Sans?
I took the parent comment to be saying, "look, there are all these preexisting sans typefaces, why not just take one of the ones on this list". The answer: because they'd have to arrange to pay, and to source them from the commercial services that make them available.
I agree that there are other typefaces they could use! I was mostly commenting on how a list of faces that includes Avenir, Univers, and FF Meta was probably not the best summary of the available options.
