This is why the Apple Watch doesn't need a killer app

This is key. I think these days we basically don't care about a single killer app, partly because we know that if there's a CPU, screen, internet connection and the ability somehow to run software (apps or web apps), the rest will get figured out later by us and by developers. And critically, because of this, the killer app could be different for everybody.

Apple has devoted one of only two buttons on the Watch to communication, suggesting that the company thinks this will be a big reason for buying one; the health tracking stuff will also attract many for sure. But for you it might be neither; for you it might be an app that hasn't been invented yet.

There may yet prove to be a single app that makes the Apple Watch irresistible to most people, but I don't think it matters. At least to begin with, people will buy the Apple Watch because it's enticing and exciting, because it looks good and because there's obvious potential there. They might not have worked out what they'll do with one, but they just want it.

There is, after all, precedent. The iPad still doesn't have a killer app; people bought them, at least initially, because they were exciting and had obvious potential, but rarely, in contrast to VisiCalc and the Apple II, because they had a specific task in mind for it.

Ask most iPad owners a year on, though, and they'll tell you it's insinuated itself into parts of their life they could never have imagined, and become if not indispensable then certainly integral to how computers fit into their lives. I think the same is likely to be true of the Apple Watch; its killer app might be different for everybody. After all, as Apple said, it is the most personal device it's ever made.