I'm not sure 10km/h give or take is going to make a meaningful difference in terms of damage upon a crash. But I'm no physicist. However I guess it may be a matter of population density too. Near me there's large stretches of land between places and there only two lanes both going the same direction. Right for travel and left for passing/overtaking. The real danger is the jackass weaving at 140+ km/h and the set limit isn't going to make a difference to them no matter where it's set.

Edit: I understand there can be a cultural component too. Does everyone where you are adhere to the limit so closely? If so I'd follow suit when driving there. As others have said the flow of traffic is where it's at.