If I were a regular WSJ reader, I'd subscribe, but I'm only reading the occasional WSJ article that's linked here on HN. Having the Add-On bypass it is more convenient than using the FB redirect snipplet and that's about it. If the WSJ doesn't want any non-subscribers to read their articles, then it's on them not to provide exceptions (FB referrer).

For me, it boils down to reading between 1-3 WSJ articles a month by bypassing the paywall or reading none at all if they don't allow me to, since I don't consider the consumption worth the price (which includes handing over data to a US corporation) I'd have to pay. That money is better spent on a local news outlet that provides me with news I consider more relevant to myself.