the bot is immediately recognizable as non human by other bot players.
there are many ways to make it more humanlike
1 - most important: don't use always the same speed for everything. if you have 7 minions it's obviuos you are against a bot if all of them attack with the same speed. also, if there is a clear board and bot has many minions, all of them should go face immediately, like a human does. if you see all minions take several seconds for each attack, it's obvious it's a bot.
2 - do "fun" things. example: if bot has lethal, just before killing opponent bot could heal oppoonent's hero (if lethal is still in effect, when using a priest), ping one of its own minions (if using mage) or attack a minion instead of going face (if the rest of bot minions can kill opponent anyway). the kind of things people does because they are bored.
3 - make some "error" and use "Oops" emote (just randomly, at the end of some turn, once in a while, even if no real error was made. opponent won't know anyway).
4 - randomly, once in a while, the bot could simulate player become angry (if opponent, for example, clears the board or opponent is 30 health and bot is close to death). bot could spam Threaten emote 10 or more times in a row. Or just Squelch opponent end Threaten it thereafter.