Full time employment isn’t the purpose for which a digital nomad enters any country. They already have that in their home country, and presence in the US (or any other country) doesn’t enable them to fulfil their duties in a way that they couldn’t do in any other country.

A digital nomad enters a country exclusively to pursue the pleasure of tourism. The entire point of digital nomadism is that those people have realised they can engage in tourism year-round.