I've been reading up on performance benefits of using and to help fetch critical resources but one thing I can't quite figure out is whether these techniques still offer benefit when the resource is located on the same domain as the page that's requesting them.
E.g. I'm optimizing a page at abc.com Should I add a <link rel="preconnect" href="abc.com">
or <link rel="preload" as="script" href="abc.com/main.js">
to my markup? Or will it not have any effect since the current page is on the same domain as the link href values?