It's not overkill to get a dry cabinet even if u are using a prosumer digicam. Fungus will grow in the lens of any camera regardless of whether it's a SLR, prosumer or even a compact cam. In our tropical climate, fungus thrive in this kind of hot and humid condition unless you store them properly i.e. in a dry cabinet. A air-tight container with silica gel is another good option but you gotta check regularly to ensure that the gel don't turn pink and, if so, you gotta heat them up to get back to its original bluish color. In the long run fungus in the lens will affect the picture quality and, if u intend to sell away your camera later on, people will not want to buy it if there is fungus on the lens. It's a good investment to get one and I consider it necessary to get one. A small dry cabinet costs about $100 and besides cameras, u can also store your video tapes, floppy disks, etc. in it.