things work as expected if the goal is copying by value, rather than referencing that value. However objects are different.
If I want to work with a copy of an object, rather than simply making a reference to it, I will want to use some kind of cloning method. _.clone is one such method.
Like a lot of methods in lodash, this functionality is now native in modern browsers. As is the case with Object.assign. However because I do care at least to some extent about backward compatibility, and do not want to invest a great deal of time making platform specific client systems, just suing lodash will help march things back a bit more. This is maybe the main reason why projects like lodash, and jQuery, are not dead just yet.