Small nitpick regarding Hearthstone: Its branching factor is really not that high. Higher than Chess, but not in the same category as Civilization, which gives you thousands to tens of thousands of potential inputs every turn.
In Hearthstone, you have a specific amount of options you can play (anywhere between 0 and 10-ish), and each option may have one or more targets (usually again between 0-10 ish). This sounds high, but you're able to discard a lot of those options much more easily than you would in Go/Chess (eg. damaging yourself is seldom a good idea).
There's often multiple options you can play per turn, but each option has to be evaluated under the current state of the board since playing a single option can radically alter the game state. So a much fairer approach is to look at a branching factor of about 15, with multiple successive "turns" (eg. each option is a single "turn", and you can play multiple turns before ceding control to the opponent).
In Hearthstone, you have a specific amount of options you can play (anywhere between 0 and 10-ish), and each option may have one or more targets (usually again between 0-10 ish). This sounds high, but you're able to discard a lot of those options much more easily than you would in Go/Chess (eg. damaging yourself is seldom a good idea).
There's often multiple options you can play per turn, but each option has to be evaluated under the current state of the board since playing a single option can radically alter the game state. So a much fairer approach is to look at a branching factor of about 15, with multiple successive "turns" (eg. each option is a single "turn", and you can play multiple turns before ceding control to the opponent).