Some users find it confusing as the weekly data is based on each day instead of each workout. The reason that we display the average distance over each day is that this reflects more practical insights into your training status. Usually, training is on a weekly basis and a complete cycle is completed each week. If we display the average distance based on the number of workouts, you may be presented with the wrong info.
Here's an example that can provide some clarity. If we use the average distance by times method, you will be tricked to think that week 1 has higher average miles than week 2 and requires more effort. However, this isn't true when we break down the distance by each day.