UNESCO designates World Heritage sites in order to preserve cultural or natural assets deemed significant to humanity. The idea is to maintain these assets for future generations, but UNESCO itself doesn’t pay for maintenance. It is up to the countries where the sites are located and UNESCO will remove the certification if they’re not maintained properly.
Japan is upfront about seeking World Heritage status for cultural and natural assets in order to boost tourism, a purpose UNESCO doesn’t encourage. The issue with this purpose is whether attracting visitors to help domestic business works against UNESCO’s primary aim, which is conservation. For several years, Japan has wanted to gain World Heritage status for a group of islands situated between Kyushu and Okinawa due to their unusual fauna. Last year, UNESCO rejected a request to grant status to the islands, but the government still wants to win approval, hopefully in 2020.