I reckon that for a smarter trading ecosystem, all exchanges should create and have this feature available.
However, Bitfinex already has printed and issued billions of play money hehehe.
In response to customer demand, we're pleased to announce Paper Trading is now live on Bitfinex. This feature will be available on newly-created sub-accounts, helping users test strategies & trade Bitcoin in a simulated market environment without the need to deposit real funds.
Benefits include:
Simulated Bitcoin trading without the need to deposit
Create multiple paper trading accounts to test various trading strategies
Ability to share paper trading strategies and ideas within the Bitfinex Pulse community
Test balance available to all users for paper trading strategies
No risk to real account fundsSource https://www.bitfinex.com/posts/477