This is less of an issue with exclusively plant-based composting, but some materials really benefit from a hot compost, and some compounds and pathogens are only broken down or killed in a hot compost. This is less a compost tube and more a vermiculture tube.
But I have done similar things with select materials in a hugelbeet with
raised bed sides. The only things that went in the tube were fresh kitchen scraps and
coffee grounds, so it was really more of a worm feeder, but that doesn't mean it wasn't a fantastic way to take the food
energy in my kitchen scraps and distribute it throughout my hugelbeet. And the worms did all the work.
I don't know that I would necessarily classify compost tubes as gear, but rather technique, as it's a rather simple setup that you build and install yourself, with no set parameters other than those imposed by its function. That said, I like the idea, especially in a situation where it can be advantageous for soil fertility in planters and container gardens in living conditions that would otherwise not allow soil-based (rather than bucket- or container-based) composting.
-CK
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
-Robert A. Heinlein