That's not a big deal when you have the tab open, since it checks for changes every 50ms. Normally, after executing a bang through your skin, you'd have to wait for the extension's info watcher to pick up on changes to the site. I've also configured the extension so that it automatically sends info updates to Rainmeter when the user successfully activates a command. This is an unnoficial fork of the original companion extension, which has been modified to enhance the experience on YouTube and Netflix and to update the site scripts more regularly. The browser extension required to use the WebNowPlaying plugin for Rainmeter.

Web Now Playing Companion Extension - Unofficial Updated Fork