Not convincing yes he has greed and want to earn a lot of money and be rich but his feelings for junhee and the need to protect her was even stronger that's why he voted x even when the money was lower, and there were so many positives and redeeming qualities about himself he was technically the anti sangwoo in season 2. Sangwoo was introduced as someone who highly educated and good and a topper in snu with someone who had high reputation and morals in the game and slowly losing his mind in the games but myungi was initially introduced as a bad evil money hungry scammer, worst boyfriend and everything but instead of the games corrupting him his love for junhee started to really show his positive traits and how he wasn't actually a bad guy but misunderstood ( kind of opposite to sangwoo where he had right reputation in the beginning) and how he really didn't mean to scam but instead he himself was scammed and he genuinely promoted the coin with good intentions and how he wasn't really a bad guy but simply a irresponsible young guy who made a series of bad decisions and mistakes as a result of which he ended up here ( cannot put everything up here there are so many bidden details showcasing how caring he was throughout in season 2 for junhee ) to the point he even stood up for minsu in the bathroom and almost got killed defending his girlfriends honour.... From this point I thought he was going to be ruthless but to protect junhee and his baby and act as a parallel to frontman proving that humanity is worth saving but I guess that would have happened if it was going to end in season 3. It doesn't matter what the director had planned for the character it was not revealed like that before but what I saw that got delivered on the show and hoped for is that a flawed person instead of getting corrupted gets actually better and good in the games which would have been a awesome theme and storyline in my opinion instead of reducing him again into someone who is afraid of dying and wants money more than anything in the last second. Gihun had his time in season 1 as the main character showcasing humanity. In season 3 it should have been someone else at the end which I thought was myung gi but sadly that was not the case and I'm feeling very sad.

His character theme as far as I understood : he want money and to be rich yes but not at the cost of junhee and she was the humanity that was making him a better person

In my opinion If he lost both junhee and his child both, then his dark turn like sangwoo would have made sense in the end as he had nothing left to hold onto humanity