I am in the exact same situation. I can't distinguish between athletes with the same name, and I can't associate their activities with a specific datetime.
I'd like to keep running weekly/monthly distance totals per sport type so that we can give internal shoutouts to our top athletes. I'd also like to be able to collect enough data over each year to calculate our most improved athlete, or most consistent athlete, or even do things like call out our early morning athletes or late night athletes. I also want to keep track of how many times we've "travelled" around the world.
The clubs/{id}/members/ and clubs/{id}/activities/ end points seem to give very little data.