Performance gains of "Parsoid/PHP ... roughly twice as fast on most requests as the original version" are bit more than a casual bonus and into territory of pretty dang awesome in my book.
I totally agree, but on wikis of a smaller scale it's not a difference of performance, it's potentially being able to use some of these MW components for the first time. It could be 10x faster than Parsoid/JS and that's irrelevant compared to being _possible_ on a service that won't let you run Parsoid/JS.