Why should an API return 'void'?

Question

When writing an API or reusable object, is there any technical reason why all method calls that return \'void\' shouldn\'t just return \'this\' (*this in C++)?

For examp

Answer 1

The technical principal that many others have mentioned (that void emphasizes the fact the function has a side-effect) is known as Command-Query Separation.

While there are pros and cons to this principle, e.g., (subjectively) clearer intent vs. more concise API, the most important part is to be consistent.