What is the point of Overworld in the game?

[Jin-]

Well if you just do "this boring, that boring" like for example, fishing, then every open world stuff is just nothing for you. I know it's optional, but at least giving it a try won't hurt you know

There's a reason most people sit in the hubs. I know it might hurt you. Maybe after you play few other games like ESO or GW2 from the same game genre you can see how lifeless and empty our zones are