It's all about the speed. Last night's 10-mile joggling extravaganza included 6 x 1 mile speed intervals with two minutes of jogging (joggle jogging?) in between each. I got a rush out of blasting past pedestrians and hearing little snippets of exclamations, like "No waaay!" "Cool!" "You rock!" "That guy's...!" "Holy...!" "Oh my...!" and "What the...!?"
The main reason for using miles is that joggling 10 miles seems much more manageable to me than 16 km. Kilometres simply psyche me out. Joggling is quite bit harder than running, so I'd rather have larger units of measurement. A 20-mile long joggle – piece of cake. A 36-km joggle – forget it, too many units.
The other logic of measuring in miles is that four laps around a standard outdoor track equal one mile (or just shy of a mile, if you want to get technical), so it makes things easier to calculate in terms of track workouts. Even when I'm doing intervals on the road, I usually think in terms of half-mile, one-mile and two-mile intervals.
And finally, the Salt Lake City Marathon is in the U.S. – that stubborn non-metric holdout – so I might as well get used to setting my pace in miles. I remember the first time I ran the Boston Marathon after training in kilometres, having no clue whether of not I was on pace. I recall crossing the 10-mile marker, looking at the clock thinking: "I have no idea what that means." What it meant, I would discover much later, was that I was running way too fast, and would end up completing the historic road race looking like a very sick, inebriated geriatric.