This policy shift is mainly symbolic. It was also pretty much inevitable, given China's response to the 2016 international decision concerning the nine dash line.
From a real politik point of view, the US would have to either remove its influence from the region - and losing its allies in the process to pressure from Beijing - or step up, sooner or later. I don't think anyone following US policy during the last decades would gamble on the former happening rather than the latter.
Does this means anything concrete as far as the region is concerned? Not really. Or at least...not in absolution.
US is slowly building up the pretext for war in the SCS with China.