It's an incomprehensible sorting process, and it's just a waste of stamina and coins. I think they are intentionally trying to get money out of us.

There are three daily challenges, but they are all (all) considered unhealthy, so stamina and coins are wasted and the IP challenge has to be passed. The promised one month will arrive soon (December 23rd according to my calculations), but I think it's time to announce it.