It was innovative in recognising moves which had previously been only defined in terms of their exponents: the Chudley-Smith progression was recognised as the first modern cross-hatch, and the word 'pickering' was used for the first time in a ruleset.
Crescent '31 was also the first ruleset to be used uniformly across the grand-slam tournaments, and was finally recognised as the official world standard in 1935, when the "All-England Mornington Crescent Club" was amalgamated from the central London clubs. [Edward Cholmondeley-Davis]? won the World Championship that year, the first champion under Crescent '31.
Despite the many other new rulesets that appeared in the late 30s-40s (including [Crescent '38]?, [Praed Street '41]? and [Mark Lane '46]?), Crescent '31 continued as the ruleset of choice for many tournaments, including the World Championship (although Praed Street '41 was used for the 42-43 tournament) until it was superseded by [Marble Arch '54]?. Aficionados still like to resurrect Crescent '31, although in recent years it has fallen into increasing obscurity.
This ruleset is also known as the 1931 IMCS/CAMREC Crescent Treaty Ruleset.