Leaving your job can either be a devastating or liberating experience. It's usually a lot more positive when you're leaving out of your own volition in search of better opportunities elsewhere. Getting fired can be a lot more upsetting, especially if you had seen yourself staying at the company for much longer. However leaving your job manifests itself, you at least know your next step. If you're laid off or fired, you can collect unemployment. If you quit, you start applying to other places. Those streams rarely cross.
One worker recently went through a horrific situation of getting fired by being coerced into quitting. Their boss told them that in order to get their Christmas bonus, they needed to resign from their job. Aside from this totally being illegal, it's just cowardly. Why couldn't they just fire this person with their whole chest? What's the use in trying to deny them their unemployment checks?