Did you read what the addon is about? It’s not an adblocker but is to be used in conjunction with one. All it does is circumventing the adblockerblocker. It specifically recommends being used together with uBlock.

Btw, I use FF with uBlock. But I am not everyone, so when I stumbled across this, I thought it might be helpful for some people.

And I found it ironic, that Googles own extension store contains an extension that circumvents the YouTube adblockerblocker.