Board Thread:Questions and Answers/@comment-124.191.164.13-20160903033725/@comment-26484417-20160903070354

Vast majority of people--regardless of their position--would be basically useless in the outside world, because their techniques are based purely or mainly on Shinsoo. Even when they seemingly engage in a physical activities (e.g., punching, blocking, throwing, etc.) most of it is facilitated via (Shinsoo) Body Enhancement and their performance without Shinsoo is questionable; Ran could still kick and punch, but only with a strength of his body (i.e., that of a child).

That said, the Outside World isn't exactly devoid of supernatural from what I recall, so even if there is no Shinsoo, there may be something less potent (e.g., mana) that could be a limited substitute.