You may have noticed: in TFL, you get points based on the duration of your walk or run (number of minutes), not the distance or pace at which you traveled. We do that for the same reason that we score weightlifting based on "sets" and not "amount of weight" - our scoring system rewards effort, not fitness abilities.
We built an "effort-based" scoring system so that diverse groups of friends, family and coworkers can compete together, even if they have drastically different fitness abilities. Most likely, not everyone in your league can run a 6-minute mile (even if one or two people can). But everyone can run or walk for 30 minutes. The choice to keep going - and run the extra 5 minutes - is what we reward at TFL.
We know you're thinking it, so let us just call it out: YES, this does mean that you can slow down your run and therefore get more points. Look, TFL is an honor code-based game. You log your own workouts, based on your judgement. And you determine the intensity of your workouts, based on your motivations, comfort levels and fitness goals.... This is just another example. And we trust you.