Probably not much of a difference. These mini PCs can run at single digit wattage too and you won’t be buying new SD cards every 6 months.

The market is about to be flooded with them with Windows 10 going EoL in October.

I bet you could instead use an ESP32 for GPIO and just connect it remotely to whatever Pi alternative you use (if needed at all). Turning some switches on and off while monitoring input values doesn’t sound very computationally intensive.

I think this really depends on the model they’re eyeballing because the Pi5 is frankly ridiculous for the price and has absurd power requirements (5V5A USB?). I wouldn’t recommend one of these unless you have a specific need like a certain hat or the GPIO pins. You can get a Dell micro Optiplex for less money and have a full fledged i5 or i7 processor with similar power usage.

Plus the RPi Foundation exposed themselves as the greedy bastards they are during COVID which is yet another reason to turn your back on them.

For something like a Pi Zero, maybe go for it, but there are similar devices out there from other companies too.