When you live paycheck to paycheck, a little bit of turbulence can have big effects. You can’t afford to miss a single check. That makes you dependent. It limits your freedom.
Not living paycheck to paycheck means resilience. You’re not afraid of losing a particular job. You can survive it. This helps with negotiating. It means you’re more likely to speak your mind. You’re less willing to do dumb things because someone in authority is being stupid. You can say “no”, leave and go find a new thing. You have time, flexibility, independence.
There’s no decoupling your job from your career when you need that next check.