But the Pi also needs to run much longer under full load to achieve the same as a modern mini PC, so it might be still canceled out in terms of total power use.

But the Pi also needs to run much longer under full load to achieve the same as a modern mini PC, so it might be still canceled out in terms of total power use. Raspberry Pi chip sets are always older (less efficient lithography/structure size) ones, as they take over the ones currently being phased out for industrial use (so they get them cheap). Those have a hard time to compete with e.g., a modern Intel N100 CPU which has a TDP of 6W but at the same time 4 cores with a max freq. of 3.5 GHz and can even use DDR5 (or LPDDR5 for low power) and is available in many form factors, often fanless with a metal body as cooler at about 150€ (if lucky) to 200€ and those models then even including (often multiple) 2.5Gb Ethernet ports and NVMe M.2 slot. That makes it at least for me an easy choice, and I am indeed looking out for using less power but still getting stuff done somewhat quickly.