As much as I agree with Cord that animals shouldn't need to justify their right to exist (and live undisturbed) by whatever use they can be of to humans, I still think that they contain vast amounts of untapped "technology" whose use could be beneficial to everyone. Very often, using animals can be a natural alternative to developping complex, expensive technologies: living beings are by far the most wonderful machines you can think of.
For instance, specially trained pigs and dogs have been used for centuries to detect truffles. Could electro-chemical sensors be developped to do that job? Most probably. But what would be the point? A dog's nose is as sharp a sensor as you'll ever need. In the same way, I heard some pigeons had been trained to peck at a button when they caught glimpse of anything yellow, red or orange (the usual colour of a life-jacket). Placed in pods attached under helicopters, they're used when searching for survivors at sea... There again, a bird's eye is a little marvel of optical technology that has been around for millions of years (even though colour recognition is a well-mastered technology nowadays).
I think we're a bit too fast to look for technological solutions to our problems. Nature contains overlooked treasures of technology. Doing photosynthesis (using sunlight to generate organic matter) in a lab requires amazing ammounts of energy, when any blade of grass worth its salt does it without even thinking about it.
The benefit to animals might not always be obvious (anyone heard of that homing missile guided by a trained pigeon in its head, which the americans were trying to develop somewhere around WW2?
), but as a general rule I tend to think that any task for which we choose a "natural" solution over an energy-consuming "technological" one contributes to making our planet a tadbit cleaner, which is a good thing for animals as a whole.