I honestly haven't tried it myself, but the reason Ron recommends a particular yeast is generally because it supposedly comes from the brewery he's writing the recipe for. The recipe in question is probably from Eldridge Pope, was brewed by them, or was from a nearby brewery that is now defunct with no commercial yeast available.
I've wondered the same thing with WLP099 as far as its flavor goes. It's only called High Gravity because it is supposedly the yeast used in Thomas Hardy (or was at one time). It was likely used for beers across a whole spectrum of gravities at some point. If you try it in something like a mild or bitter, please report back with your impressions.