The way it works in WINR is that there are 1-sided liquidity pools. If gamblers win they take from it but when they lose which is expected over time, the pool grows and those who provide liquidity earn part from it (only 20% apparently which is a bit too low). I was willing to put part of mu BRETT stack at risk to test it out but if feels like there are some issues either displaying the proper numbers or something else which isn't fully clear. I hope they give an update soon and if possible I would likely withdraw my stake there again. The rewards aren't worth the risk mainly because of the smart contract risk where trust is somewhat lost now.