Copying an artist’s or designer’s work is one of the best exercises to learn design techniques. It is one of the most effective ways to learn such things as spacing, the way colors interact with each other, font design, etc. You are literally taking what an artist has become good at and having them teach you their strength in design. Every designer has their strengths and weaknesses, and the best way to learn something is by doing it, so it stands to reason that if a designer takes a work by David Carson and literally creates right over the top of his original, you will learn an enormous amount about his layout, and sensibility of design.
It was always frustrating to me that design schools so avidly push students away from any form of copying for fear to plagiarism. Plagiarism is very serious and designers need to be held accountable for where and how they reference work. But ignoring copying as a teaching tool due to fear does a disservice to teachers and students alike. As long as designers are copying design for the sake of learning something, and not passing it off as their own, copying can be incredibly effective.
Copying can be a great teaching tool to learn almost any technique. It should be used by students and veteran designers to expand the abilities and add to their range as artists, just don’t sell it as your own.