Some applications of Levenshtein, such as spell checking and google suggest, seem like game physics in that they are consumed by humans, and gross approximation

Some applications of Levenshtein, such as spell checking and google suggest, seem like game physics in that they are consumed by humans, and gross approximations are good enough - even with occasional glitches. Speed trumps accuracy. Unless there're clever compilation algorithms to calculate edit distance really fast, that fall apart without a metric...?