One of the interesting aspects of YANG is the kind of tooling it enables. Because of it’s structured tree-like nature, it naturally renders itself to have corresponding API (corresponding to each model). These API can either be generic path-based (similar to XPath) or specific to each data model (as it is in YDK).
This API can then be used in various tools which may be used to configure and monitor devices which support the corresponding models. Also applications which deal with processing the modeled data can make use of such API.