Although components are meant to be similar when used throughout your artboards, there are many elements you will want to change depending on the use case.
Sketch Symbols allows you to override text and swap out nested symbols. But you cannot rearrange elements in a symbol or change colors of symbols without a complex set up of predefined colors that are saved as Symbols themselves.
Because of the limitations of Sketch Symbols, you are often forced to either break the link to that symbol to change things how you want, or go back into the main symbol and create a new variation for that single use case.
In Adobe XD, Components behave very similarly to a normal group of elements. You are free to change position, scale, color, and style of any element in a Component instance without affecting the Main Component.
You can also add new elements or delete elements in an instance giving you endless options to control the look and feel. This instance will still always inherit the properties of the main component that have not been overridden.