Why would i concede after a win? Just to lower the winrate? Its an option for those who play ranked with bot?
It's for ranked. It's used to manipulate your current rank (so the bot doesn't start playing better players @ higher ranks, thus lowering the win-rate). If you're playing ranked it helps you squeeze out an extra win or two per hour (which adds up if you run it 24/7). It does however add a "pattern" that might become recognized as bot-like behavior though. Use at your own risk.
Its for farming Gold portrait. If you find a good deck you can have a 80% or more win rate. And so games are quick and easy. If you stay around rank 20. And yes it does add a "pattern" that might become recognized as bot-like behavior And i suggest not to do it. at the current state with botting and blizzard. But just know people who dont bot and want gold portraits do it to.