Correct. Usage is the best thing that can happen to your camera.
Fungus likes: stagnant air, darkness, high humidity, organic material (e.g. sweat, skin particles, dust ..)
A dry cabinet helps to keep all gear neat and tidy at one place. If you like you can also put in flash (remove batteries, so you don't forget to charge them) and other items that don't really need controlled humidity (filter rings, adapters, flash diffuser, other bits and pieces).
I don't use Silica gel, can't say how much is needed. Get a hygrometer and play with the amount of silica gel in the box till you reach target range (~50% RH).
