I think it's very consistent with his personality that Nakwon would use Mokhwa's money for extra selfish purposes like maybe jealousy over the ex-boss, or not having Ms Kim be in control of the money, or because he thinks Mokhwa will outright reject it if it's Nakwon's own money, or simply his hubris thinking he knows what's best for Mokhwa. Author-nim is reminding us that he's still a very flawed character. But I'm pretty sure Nakwon can replace every cent of it, in cash, so his motivations and his machinations make it all the more interesting.
I think it's very consistent with his personality that Nakwon would use Mokhwa's money for extra selfish purposes like maybe jealousy over the ex-boss, or not having Ms Kim be in control of the money, or because he thinks Mokhwa will outright reject it if it's Nakwon's own money, or simply his hubris thinking he knows what's best for Mokhwa. Author-nim is reminding us that he's still a very flawed character. But I'm pretty sure Nakwon can replace every cent of it, in cash, so his motivations and his machinations make it all the more interesting.