I have a Luckfox Pico Ultra-W running a ‘buildroot’ linux with a camera module that I use as a security camera. It cost me about A$33.
I also have a Luckfox Pico Max running ubuntu simply to run smokeping 24x7 monitoring - about A$30.
Finally a ESP32 CAM Camera Module With OV2640 camera that can be bought for less that A$15 (not linux but just FYI).
True - but don’t forget cost of power ($ cost and environment cost). These old brutes consume a lot esp. compared to the SBCs.