Maybe I misunderstood the current situation? Of course other services exploiting it isn't intentional, but giving a free pass to one of their own services was definitely intentional?
The article mentions: "the actual Skype Dashboard widget does not seem to utilize the backdoor into the Skype Desktop API despite the name" which, to me, lends more credence to the assumption that this was perhaps a test or a prototype and only included in the shipped version accidentally.
Where it could instead be a bug or mistake that was not intentionally included.