I just checked. Still works. But I use ESR Firefox, if at all. It is a hassle to activate temporary addons on Firefox.
In case you tried to install the zip, that will not work. You need to hit the debug buttons or whatever it is called to load a temporary extension. You need to unpack the zip somewhere and navigate to the manifest json there and load that as a temporary extension. Maybe even activate rights for that extension. It's a hassle to do this every browser start. I would rather recommend a bookmark with the exclusion filters on FF.
As far as usefulness goes, the two tampermonkey scripts are better anyway and there is no need of this temporary extension things. But you do need an extension that cun run such scripts.