Plus, the conversion of sunlight to wood is maybe 0.5-1% efficient if you’re lucky, compared to ~20% for solar.

So about 0.001-0.002% as efficient as solar, up to 5 orders of magnitude worse. With the advantage of less intermittency, I suppose, but both are solid state energy converters; I wouldn’t claim thermoelectric is “lower tech” except that it’s way less efficient and with more environmental footprint due to that inefficiency. A battery to solve the intermittency would be still a much better trade IMHO.