Super interesting fact, OP. This means one can calculate the rough number of Overwatch games that have been played since the endorsement feature has launched (June 26th, ~2 months). This is the first time I’ve seen any recent info on how large the active playerbase is.
Edit: So there’s a minimum of 40 Overwatch games per second being completed. I’m guessing the actual number is roughly an order of magnitude more (400) due to: (a) not every mode having 12 players, (b) not being able to re-endorse for 12 hours, © players not endorsing at the maximum rate possible every game.
2nd Edit: Based on a bunch of other facts, I was able to further guesstimate the number of concurrent lobbies for my SR/play time/region and it reaffirms what I had felt. When I play most there seems to be a small handful (1-10) concurrent game lobbies at once for my SR & region. Interesting to see this guess roughly correlates to officially released stats.