When passing a value to _.chain the returned result is a wrapped value ready for explicit chaining. Functions that return arrays, collections, functions, and values of any kind can then be chained together. However once done in order to unwrap the chain the _.value method must be called.
Many of the methods in lodash are properties of the _ variable that is added to the global name space when using lodash. However the _ variable is a function rather than just a plain old object, and as such it can be called and passed a value. When using the main lodash method in place of _.chain that is what is called Implicit chaining. It is more is less the same as the explicit chaining only using a method like _.sum will result in unwrapping the wrapped value, so the _.value method does not need to be used in such a case.
When working with an native array methods as long as what is returned is also an array then I can continuing calling additional array methods on the array. If I am not using lodash then I am limited to what there is to work with in the Array prototype, as well as the prototypes of other built in classes depending on what is returned.
For example there is no native equivalent of _.sum, however it is not to hard to quickly sum an array using the native Array.reduce method.
5 - Conclusion