We (The EPEL Steering Committee) are following up on EPEL issue 136[1] regarding the status of EPEL8 Playground.
Looking through the logs we see that there are still people building against playground on a regular basis. But as I look into each of those packages, the same package is built in both epel8 and epel8-playground, at the same time.
This leads me to believe that the only reason people are still building on playground is because they feel obligated to, not because they really need someplace to test things out.
So, if anyone is still using epel8-playground for something they can't get from epel8-next and/or COPR, please let us know. Otherwise we will shut it down and call it an interesting experiment.