What's exactly the point of allowing the player to get into Pripyat through ONLY one passage?

What's up with all the fences and uncrossable rivers in this game? I understand when the point is about the story and "locking" some areas for future access, but for example, once I get into Pripyat and want to go sell some loot back at the trainstation, why can't I just go through the main road south of it? Like it's so annoying on purpose to go back all around again

EDIT : Yeah I rushed into Pripyat exploration and didn't even get to see that there was a hub where I could sell stuff. I thought it was a complete dead zone. My bad