No benefit how ???Unless the HSR runs under the ocean to connect different Indonesian islands there is zero benefit in Java island only HSR
This HSR is planned to connect Major cities like Jakarta,Bandung, Semarang and Surabaya with total metro population almost 60 million people and With total GDP $435 billion. And we still not including middle size city too.
This project have a fricking big potential even if it in java alone, it take 11 hours to go from Jakarta to Surabaya with car you know.