At a high level, all counting schemes are basically streamlined approximations of stone counting. It turns out that codifying all the edge cases is nontrivial a

At a high level, all counting schemes are basically streamlined approximations of stone counting. It turns out that codifying all the edge cases is nontrivial and so the simplified scoring schemes come up with subtly "wrong" results at the margin, but this is something of an acceptable sacrifice that doesn't (isn't supposed to) change the essential nature of the game. The main difference that Japanese rules make on scoring is, essentially, codifying a matter of etiquette directly into the scoring: they aggressively penalize extending the game with unnecessary moves, which to be sure has some distortionary effects, but again, they don't essentially change what people considered the meat of the game; you'd play 90% the same game regardless of counting method, with differences cropping up basically once a player starts passing. This has far more ... pedagogical value outside the game, than the impact it has on the game itself. By far the most important rules in a ruleset, in terms of how they affect core gameplay, are the repetition rules, and even the choice of suicide rule has a more substantial impact than the differences between scoring systems.