I agree that it's a tradeoff, but not in power efficency. It's easy to shut off parts that are not being used. It's primarily a tradeoff between a) increased c

I agree that it's a tradeoff, but not in power efficency. It's easy to shut off parts that are not being used. It's primarily a tradeoff between a) increased chip size, b) number of external chip connections, c) cost, d) probability that having a small number of footprints/designs will help. So, in short: cost vs winnings from having a lean library of component.