This extension redirects requests before they've even started, making it much faster than what's possible with a Greasemonkey script. Greasemonkey scripts are also hard to discover and install these days.
Userscripts can also run before any content scripts through `@run-at document-start`. With a browser extension, you're giving up portability, security (an extension can wreck a lot more havoc than a site-specific script) and the freedom to publish without being dependant on a "store".
This extension redirects before a request is even made. `document-start` runs when the whole page is downloaded, but before the DOM is constructed, which is a lot slower. As for portability, both Firefox and Edge are committed to supporting Web Extensions, which is pretty much the Chrome extension API. This extension is not tied to any store. You can install it manually exactly as you would with a userscript. Actually, userscripts in Chrome, are just re-packaged as native extensions on install.
