It's more about frequency than priority. When something has to be serviced tens of thousands of times a second, "a dozen or so" becomes a problem. If you have the silicon that solves this, you can retain the model. If you don't then you have to resort to workarounds.

Fortunately we typically have more efficient means to deal with such hardware, but not always, and it would be a shame to break the intended model when this is the case.