Patrick Rhone has an excellent take on the Apple Watch. A different perspective coming from a fellow watch lover:

They also understand us watch people. They know that those of us with the cash or care typically don’t just have one watch. We have two or three. A sporty one, a casual one, and a fancy dress up one. Some might be OK with wearing a $50 watch with a $500 suit, and I’m sure Apple will be happy to sell them only one band. For many though, Apple gets that the watch itself needs to blend into any environment the user could be in. So, make the the band easy to switch and offer just about any style one could ask for. But, at the same time, make the watch case look good with any of them. And, in allowing this level of customization it becomes more personal still.