Yeah, sure. That could be a reason to do this.
The problem with contacts/appointments is, that there are a lot of different standards and software for it. Thunderbird for example has no appointment support at all and contacts are supported as simple addressbook. So, the question is, what software to support? Well, there is Sunbird, but the used protocol is not very practicable for large calendars.
Nevertheless: Z-Push supports currently all possible objects only with the Zarafa connector. And I think for Zarafa users that's not very interesting.
So, AFAIK there is no such application (desktop AS) and I think it will not be developed..