Some fields have a no-running rule, it's not universal. Additionally, while there is a lower power limit, there's also no MED. There tends to be no sprinting in CQB sites, but they tend to be tighter and smaller, so there's less "need," and more chance to get hurt -- plus Japanese airsofters tend to be focussed more on tactics, rather than rushing around.
At the end of the day it generally has more manners -- cheating is rarer, there's not the fighting you see (especially in the US), there's just more honour and respect all-round, IME. More clear-cut and tactics-oriented than rule-bending and sprint-and-spray ?