Yeah tbf I would probably consider just using my phone with my mobile usb-c monitor and bluetooth keyboard, if iOS was not so hostile to be used for actual work (and it does not seem simple in android either, though maybe I would be eventually able to make it work there). It would be very useful to have such a light setup on the go, as I do not necessarily need strong multicore performance all the time.
> AMD chips with TDP configurable down to ~15W
I don't trust the TDP values companies publish because there is no standard way to define what TDP is or how it is measured. At best they are consistent in how they measure them within each brand, so you can at least compare different generations.
And in any case, the question is how competitive such a configuration is vs an ARM-based laptop, with much longer tradition in the low-power space. Could be my searching skills, but looking to get a laptop recently I did not find anything in a better spot in the efficiency/performance/price axes than an air. In particular I was unable to find AMD fanless laptops anyway.
Just as an example, during light work with my m5 mac (eg editting a text file, or writing this comment while a youtube video plays in the background and a bunch of light stuff run in the background too, screen low lit) I see 3-4W total system consumption reported by the OS, while a wattmeter shows 7-9W consumed. Part of it may be hardware, part of it software, but figuring out idle consumption is actually very important for making fanless work. A lot of work a cpu does in a normal day of mine is in bursts. Much of the time it is not necessarily doing much, and you need the thermal headroom for when it is actually needed. Last time I tried tinkering with a thinkpad and linux I did not get remotely as far. I would be happy if there get to be more options.
> The question is, in the instances when you still have to wait for the machine, would you rather wait noticeably longer or pay significantly more money in order to avoid white noise
If I encountered these instances often enough, then definitely a fanless laptop would not be appropriate for my use-cases. But I don't encounter them for what I want to use it for, and the next option with a fan is a larger, heavier and more expensive laptop, which I don't need. When I needed one for my work, I got one. I also have a 16" one that stays mostly at home because I cannot carry this weight around daily and I do stuff I cannot do with an air there.