Oh yes, biochar is definitely worth it. In fact, in this age of rising atmospheric CO2, it becomes imperative to start using it on a mass scale.
First off, it sequesters carbon. If that biomass was converted to mulch, or fed to termites, or landfilled, or a host of other possible fates, it would turn into methane and CO2 in a few years, staying up in the atmosphere where it is not needed.
Second, it improves soil fertility. But you shouldn't think of it as a fertilizer like manure or
compost. Biochar is a catalyst. In the true sense that a chemist uses that word. Biochar doesn't participate in the chemical reactions of plant growth; it just holds onto the nitrogen, the phosphorous, the
water, the micronutrients that are needed for plant growth.
Suppose that the discovery of biochar's effects on plant growth came along at the same time as the invention of the oil well. After the start of the oil age, industrial civilization pretty much gave up on making charcoal and left that to the Third World. Had we kept manufacturing charcoal, but using it for soil amendment, we may not have put ourselves in the same predicament vis-a-vis atmospheric CO2. Maybe desertification would be an unknown problem, maybe we would be a lot better off.
I think without such an effective tool as biochar, it would be much harder to build a
permaculture.