. . wrote:
I guess it's since it's easier to run more with shorter stride
That was certainly one of Daniels's points in favor of higher cadences. I think he actually said that, if he took a bunch of beginning runners, many of whom have low cadences, and had them run 100 mpw for a while, some of them would increase their cadences to about 180 or more, and the others would have dropped out with injuries. But I think he overstates things and draws incorrect conclusions about the causal effect of higher cadences on the ability to increase mileage without injury, whereas higher cadence is really more of a general (but not universal) side effect of increasing mileage while avoiding injury.
Somewhat similarly, while running speed is simply the multiple of cadence and stride length, that doesn't mean it's a good idea to try to increase either cadence or stride length in order to run considerably faster; it's much better to focus on running considerably faster. You can then look at changes in cadence and stride length during the course of developing into a considerably faster runner. (Overwhelming, you will find that, at least among distance runners, stride length has increased by a much higher percentage than cadence. Conversely, as runners slow down with age, cadence doesn't change much, but stride length goes way down. But that doesn't mean that you can simply focus on increasing stride length, since the decrease in speed is primarily related to the inevitable decrease in oxygen uptake; the decrease in stride length is essentially just a side effect.)