A hidden threat in this, is that podcasting can look like journalism to many economies. If you "report" on current affairs in any way, you can fall into the trap. Mainstream broadcasters are always super-careful when staff are sent to the USA, to get the right visa. If the staffer just goes to the USA, they have to make damn sure they don't return to work, even if they take that call about some story, there is a risk…
This is true in general for digital nomads, whether they blog/podcast or even just freelance, a lot of whom continue to work a few months at a time in foreign locales on tourist visas. I've seen their blogs refer to visas as a gray area. I'm pretty sure this is a mistake.
I've never worked anywhere but the us, but as a dev I could work remotely anywhere in the world if I was certain it wasn't illegal.