RDS and related protocols like TMC have specifications for both FM and AM transmitters. Those are used to stop playback if an urgent message comes. I'm assuming you have AM stations with such signals in the US (I don't think we have in the EU) - otherwise the AM radio mandate would indeed be stupid.
edit: did some digging (it's been almost 30 years since I cared about that stuff) - seems the US was pretty late to the party for radio data channels, and side channels for AM (which wasn't of that much interest here due to the FM heavy radio landscape in Europe) only was discussed in the early 90s for the US specific variants. I couldn't find any details if that actually ever got implemented. Given that most documentation available on that topic is heavily focusing on EU I'd guess it never got that much use in the US.
Oddly enough that's also an example for bad design in that notebook: The barrel jack is soldered in. With a module that is plugged into the board that'd be significantly easier to replace - and also provide strain relief for power jack abuse. All my old thinkpads were trivial to move to USB-C PD because they use a separate power jack with attached cable.
The transparent bottom also isn't very functional - it is pretty annoying to remove and put back, due to the large amount of screws required. For a notebook designed for tinkering I'd have wanted some kind of quick release for that. Also annoying is the lack of USB ports on the board - there's enough space to integrate a USB hub, but just doing that on the board and providing extra ports would've been way more sensible.
The CPU module also is a bit of a mixed bag - it pretty much is designed for the first module they developed, and later modules don't have full support for the existing ports. I was expecting that, though - many projects trying to offer that kind of modular upgrade path run into that sooner or later, and for that kind of small project with all its teething problems 'sooner' was to be expected. It still is very interesting for some prototyping needs - but that's mostly companies or very dedicated hackers, not the average linux user.