most likely it doesn't leak because the crack is not deep enough, depending the type and make up of hose, there could be a few layers below the crack still ion good shape
not all hoses are made the same, way, some have multi layers some just one layer, all depends on design of each hose
some are designed to be more abrasive proof, and have different skins on them more or less, and layers of it!(rubber metal rubber metal and so on) that doesn't mean the hose is 100% good yet,
as pressures in a hose can cause a blow out in weaken sections from cuts and or rub thru area's
, this one doesn't look critical, but if you have the means to replace, i
it will not be a bad idea to do so! safety first! as they say
as its never fun when a hose blows on its own while in use! and can be deadly even !
and from my luck, 99% of the time when one does blow, its never ina good location or weather to be replacing, so, its always better to replace earlier then needed at a time and place you can pick, rather than when it just blows in a cold hard to get to location, HAHA!