...and the extension this article is about had about 5000 (five thousand) installs before being taken down. That doesn't really scream "priority" to me.
It may be true, but your point of view isn't the sole possible. Many people have to use more than one browser and for them, the Google decision (effectively forcing the creation of uBOL) was really painful so Hill's new product is of big value. Also, there are people who don't know anything about uBO since they never used Firefox but they probably will start to use uBOL as other blockers for Chromium-based browsers are incomparable to it.
Thus 5k downloads of uBOL are no measure of its importance.
It may be true, but your point of view isn't the sole possible. Many people have to use more than one browser and for them, the Google decision (effectively forcing the creation of uBOL) was really painful so Hill's new product is of big value. Also, there are people who don't know anything about uBO since they never used Firefox but they probably will start to use uBOL as other blockers for Chromium-based browsers are incomparable to it. Thus 5k downloads of uBOL are no measure of its importance.