It's actually better than that!Brewing tea is tailored to the plants youre feeding. Ingredients change depending on what plants youre making tea for. I dont use guano in my tea and it works great. Like they said before, this isnt to fertilize your plants, its to help create and distribute bacteria colonies to help the roots take up nutrients better. Its a supplement, not a fertilizer.
The bacteria ARE the fertiliser!
The more their populations grow, the more they release mineralized nutrients mined from old organic matter. They not only poop and make nutrients available to the plant, but are little nutrient warehouses themselves. Higher level predators, help cycle nutrients faster by consuming and releasing the stored nutrients.
Every little mite or springtail I see in my soil, I picture them as one of those little time release osmocote pellets
As for guano, use it as a source of N if you want, it's a good manure but remember you want to feed the bacteria and grow bacteria, do your fertilization seperately. Either ammend your soil or brew up organic mixes to water in at another time. You can also top dress your guano little by little, so you have less chance of burning your plants.
edit: personally guano vs chicken poo, I'd rather buy the one that's 7$ for 30lb, forget about that exotic mumbo jumbo