If you're full in Apple ecosystem, like my GF, you get:

- Shared clipboard across devices - Shared documents - Shared browser - Shared passwords - Free, quality office suite - Interoperable devices (use iPhone as camera on Mac, for example) - Payments across different devices (use clock to pay, for example, shared with your iPhone)

All of this with just one account without any third-party service.

And billion of things more, probably, I'm not a full Apple head.