1) It would cut down on paper useage and thus be enviromentally friendly.
2) It would reduce the amount of paper waste that goes to landfill, saving local authorities money.
3) It would protect the elderly and vulnerable from being taken in by bogus junk mail and scams from illicit people and companies.
4) Ligitimate companies or individuals wishing to advertise should register with their local authority and be granted a licence to ensure that they are fit and proper people to ply their trade.
5) Create a local authority magazine paid for by those 'bona fide' people/companies wishing to adveritse, having been vetted by the local authority.