Watches are complex things, full of gears and the like, keeping time precisely and exactly. And the Arena Metasonic puts all that complexity right on display to stunning effect.
Of course, when you're charging $900,000 for a watch (yes, $900,000), I guess you need to show people what they're paying for. And a view into the crazy-tiny interior workings is one way to do it. But yeah, wow, $900,000. For a watch.