I don't buy it. Probably just someone trying to drum up investors. As has been the long running scheme for DECADES there for that supposed treasure. So many have been "found", and .... sure enough, all they have to do is gather investors to dig deeper for the rest, or investors to bring it up from the sea-floor, or investors to pay the taxes, sneak it out of the country, smelt it, find the rest, etc....
Sadly, there is no shortage of investors who lost their $$ on Yamashita investment scams. And I bet this is simply the next in the long running tale. Because since SO many people there believe this (thinking it certainly in every cave, and beneath any funny rock with a squiggle on it), that investors there are not hard to find. All you have to do is show them a map "that was passed down to you from an elderly WWII vet", etc... and ... presto ... investors.
And notice that even the article link itself admits no proof, other than someone's youtube video. And last I checked, youtube was FILLED with fanciful stuff, purporting to show UFO's, bigfoot, magic stuff, etc..... Sorry. I'm not buying it.