While you certainly can do annealing and depletion gilding with a kiln, it makes more sense to do both with a torch, in my opinion, It is quicker and takes less energy and also helps students learn to gauge temperature when using a torch. When making a jewelry piece, you often anneal multiple times, and going back and forth to a kiln makes little sense. The same is true for depletion gilding, which takes multiple cycles of heating and pickling. Enameling can certainly be done in one of the front loading cube kilns, as can metal clay, but both can also be done with a torch or with a much cheaper hotplate enameling kiln. The hotplate kiln is about $175, whereas the cubes are about $1000 or more, esp. with the programmable feature. Temperature of the hotplate could be gauged by eye or using orton cones. You could get two or three of the hotplate kilns for less than the cost of the cube and spend the rest of the money on something else. You would need to exercise some care with the hotplate kiln, but students will need to exercise just as much care with torches, which I assume they would be using.
A programmable kiln might be nice, but not entirely necessary, for heat hardening sterling or Argentium. A programmable kiln is very useful, as has been mentioned, for flask burnout and it’s also great for heat treating gems, but almost no one does that. If someone is telling you you need a programmable kiln for annealing, depletion gilding, enameling and PMC, perhaps they don’t know much about these processes. It would make more sense to me to use a low tech option, as many students would not be able to afford a $1000+ kiln and should learn alternate, cheaper methods they can duplicate at home.
It’s not uncommon for school workshops to end up with all kinds of stuff someone decided they needed that isn’t used, so consider who will use the kiln and whether it is really necessary or efficient for your uses.