The under 30 thing is I assume because they are trying to tackle a certain type of unemployment within a specific group.

Several industries or locations use bonuses similar to these to get people to stay for a length of time (sometimes jobs no one wants or often in locations people don't prefer (which is another part of this policy actually), and it does work in those cases, people staying far longer than anticipated because they put down roots make ties etc. Is similat principal to granting visas to people to go to regional areas and they have to stay a certain length of time.
The media and the parties both annoy me with the lack of rational and detail given, the amount of info we are given how can we ever really decide if agree or not.