I dug up my Pi2 for a project the other day. The plan was for it to be a USB serial to network bridge for up to six devices and to use ZMQ pub/sub for passing commands and telemetry. Most telemetry strings were only 500B but I sometimes see two sequential 32KB mega strings for dumping data. The Pi was choking on the mega strings and they were getting cut off early. I spent forever trying to debug this and eventually figured out it was a hardware issue when the code ran fine on a modern PC. I tried a few tricks to get the Pi to cache more USB data before giving up.

I bought an old Lenovo M92 on eBay, threw in an old 500GB HDD, and it worked perfectly for the job. I had thought about just buying a newer Pi but the 14 year old Lenovo offered better specs at only $38. I promptly bought another more modern version for $100 for my desktop.

Based on benchmarks for an identically specced machine [1], a new Pi 5 edges out on single core performance and TDP but gets beat badly on multi-core and price (4-5x, even on eBay!). There also would have been the extra cost of buying a case for the Pi. I could have spent even more money on a newer mini PC that blows the Pi 5 away entirely. Obviously a Pi (even a Pi 2) is plenty capable of many tasks, I have a Pi 3 running my home assistant but it's hard to justify the extra cost over surplus thin clients that can be purchased for much less. The Pi does have its GPIO bank that's just not offered on any mini PC but I can barely remember how many times I've needed both GPIO and a whole PC-like stack to run code, an ESP8266/32 have worked fine. An external PCIe bus is cool but again, unless you're doing some really unique edge computing, not really much of a selling point.

Power consumption is a concern but they are both so low that unless you're operating off a battery, power consumption is negligible relative to everything else in your house. It would take 2 years to make up the difference in price running at full TDP (38 vs 12W). 38W is low enough that fan noise is barely a concern as well.

Size is also a concern but the difference in size is negligible unless you're trying to cram as much compute power as possible into a mini rack. A mini PC is probably the same size as your home router so just put it there.

I just really can't see the need for running the full size Pis anymore. An old mini PC does a better job for cheaper for server tasks. A Pi Zero 2 or even a Pico are much more inline with the classic Raspberry Pi ideology.

[1] https://browser.geekbench.com/v6/cpu/compare/4383152?baselin...