This is an open-ended question and somewhat hard to give a very definitive or precise answer and most of the time one might start with ‘It depends!!’. However frequently this pops up in the various meetings with varying audiences and an answer or explanation might or might not satisfy the audiences. Here is my attempt at it
Lets Review Basics
An AEM Component is a piece of UI and two or more components arrangement creates a web page.
Web pages can have distinct layouts and these layouts are created by arranging components in different order and/ or numbers.
Templates are used to predefine the layout structures for a webpage and ultimately create web pages from them.