Of course the real-world reason is that it's cheaper to shake the camera and set off a firecracker than to build a scale model just to paint a burn scar on the side.

But my thoughts were always that the in-universe reason had to do with the modular nature of federation starships.

In almost every episode, someone on a starship either suggests rerouting something, shunting power from one thing through another, bypassing something, compensating for one power source with another etc.

It seems that in space, being able to re-configure everything at a moment's notice is important, and to be able to do that, you need easy, fast and direct, access to everything, therefore it needs to be immediately accessible, ergo high voltage power directly behind the controls.

The lack of seatbelts goes right along with it. If a console blows up in someone's face, the next guy over needs to be able to quickly move down and take over. Don't need to have to be fighting with seatbelts when nobody is steering the ship.

I don't know why they don't have safety glasses however....