As others said, the difference is very significant. Real-time systems show up especially in industrial control and safety systems. For example, take a logging

As others said, the difference is very significant. Real-time systems show up especially in industrial control and safety systems. For example, take a logging harvester, which cuts down trees and strips their branches and bark. It has a control panel for moving incredibly violent, dangerous machinery. It is truly critical that you can guarantee that, for example, sensors which detect a problem can abort something within a very tight latency budget.