Actually COSS price is also volatile so total value of your coss holding might deplete more than what weekly profit you have got from them in total. There are different exchange tokens which can be used for discount in trading and also can get profit shared by the exchange. For excample Binance coin (BNB) and Kucoin Shares.

I don't think we can consider them as passive income opportunities, but they are good to get discount in daily trading.