So it works "much better" despite being more expensive if you need to buy one and apparently harder to use (for the Raspi I can just download a Linux distro that just works)?
It's certainly interesting, but IMHO not obviously better.
You get wifi + bluetooth + cellular, a screen (always useful for debug). Spend more if you want more ram, more processing power. $80 for a IP68/IP69K one, that's good.
I just can not see how spending more on an elaborate raspberry setup, to have an overall worse solution in the end can be a better idea.
Your raspberry needs a case, a SD, etc. Cost add up.
A Pi Zero with WiFi costs about $10, case costs another $10, a name brand 32 GB SD card runs $10, and a 3.5" screen runs about $20 for a grand total of $50. A screen won't fit in the stock zero case but the zero does have a micro HDMI port.
I just can not see how spending more on an elaborate raspberry setup, to have an overall worse solution in the end can be a better idea.
Well none of that is true, so there's that. As an added bonus you don't have to exploit security vulns to get root on a Pi.
Leaving the screen aside, does the PI also has a battery and 1G of RAM?
That's what the $57 new phone has.
EDIT: it was a rhetorical question. Never mind. Keep spending on Rapsberries, while I will keep spending on waterproof devices with a battery/screen/camera that are sold as 'phones'
Most of us already have free SD cards laying around, and reading the fine article’s scenario the phone which the author already owns and carries around also doubles as the screen, so no need to buy a second phone. So I read it as costing around $20 for the base setup described.
And you don’t need to trust a sketchy flavor of a phone OS or other sketchy phone subsystems made by vendors who do not have tight controls. Unlike Pi, phones are a highly targeted device type by certain governments including governments of countries where phones are made.
Worth mentioning Termux too, which works without rooting. As such it won’t give full control over the phone, but worth sharing the knowledge that you can install a working Linux environment on Android straight from the Play Store.
I use mine to run youtube-dl to download audio only versions of YouTube (I like long interviews, talks etc), save data and can listen with screen off.
A Raspberry Pi Zero W with case and SD card is ~20€ and smaller than a smartphone. Usefulness of the additional phone features really depends on what you're doing. The Pi has features the phone doesn't (i.e. GPIOs) - but again only useful if happen to match what you need.
It's certainly interesting, but IMHO not obviously better.