Little bit total crap. The only reason that the MC can say that is because Hyeonsoo is rich, because he has a MASSIVE safety cushion in case Hyeonsoo ever decides to give up. Watch over him? Yeah, no shit, because then he is still literally secure.
And the only reason that the MC can take his own advice is because he is the MC and everything will work out for him. Imagine all of the people who go off and pursue their passion to the point of ruin because they didn't want to settle. Imagine the failed musicians or artists or anything like that. Yes, some will succeed, but there are clearly others who should take the safer path EVEN IF they truly enjoy painting, music, etc. It's because you need to live. Hyeonsoo with his family's money and the MC with his plot armor are guaranteed to not be in any serious danger. That's not realistic, though.