As it happens the toggle did not enable the feature to work, but if it’s showing up in the latest builds of Chrome OS then it is likely it will crop up when Google officially launches it.
Excitingly, clicking on the flag in the settings app reportedly refers to Nearby Sharing for Windows, Mac and Linux versions of Chrome. So while the operating systems themselves might not be supported, running the Chrome browser on them might enable a cross-platform sharing system for a whole host of devices through Google’s Chrome browser.
Despite this news its still unclear if Nearby Sharing will be a file-focussed feature like AirDrop or whether it’ll assume another form. Given it works via Chrome it might be a more limited function when using a Mac or Windows PC, but we hope not.