bitmex is a leverage trading platform where you can go long or short on Btc. In this bear market people primary focus is development of of its Technology. Likewise BitMEX Ceo Arthur Hayes working on development and future of Bitmex. Thats why they are not planning to list anymore crypto currency because they would require sufficient liquidity.
“So you know, in my, in my opinion, the futures market should always be tighter and trade larger than the underlying of this derivative. And that only happens if you have sufficient liquidity in the spot market.”
Currently there are four currencies which are listed on bitmex Bitcoin , Bitcoin Cash , Litecoin , and XRP. They maybe adding more coins in future but he said beause of leverage platform there will not be coins as much as listed on binance.