OK, I see your misapprehension. This is not true. They need storage, how much we don’t know because it depends on many unknown factors - including the rig itself.
It will therefore be a worthwhile experiment to find out if it’s viable to farm on a $5 device, plus 5 for 8GB SDcard, plus some for a 1 watt solar setup - and then zero running costs until it fails.
With zero running costs this rig would be profitable, and maybe payback the investment.
Even if not, I imagine there would be people who would like to do this. Others might want to donate them to those in sunny climates etc. All would be farmers.