The Push action adds a route on top of the stack and navigates forward to it. This differs from navigate in that navigate will pop back to earlier in the stack if a component is already mounted there. Push will always add on top, so a component can be mounted multiple times.
We can take Instagram for example;
Consider navigating to a user's profile. Then you can check user's followers and then you can navigate to their profile's too. If you do this same actions with only navigate action, when you click on an user's profile from the followers list screen will navigate to the previous profile but if you use push it will push a new screen to the stack and show the correct profile. This way you can goBack to the first screen.