Your organization has skills and areas of knowledge. Each person (or group) is good at something. You might take this to mean that the best strategy would be to give them something to work on that matches that expertise. That seems most efficient. Give them something they're good at and they'll get the most done, right? It depends on how you define efficiency. If it's how much they output per unit of time, maybe so. If it's how much business value they output per unit of time, maybe not.