Without discussing the common differences between the two similar writing fields, I would like to bring upon a few interesting observations I had while going through a good book on copywriting.
Features and benefits
While copywriters are expected to focus on benefits and then enumerate the features, a technical writer must explain the features and then enlist their benefits. More often than not, in user documentation, the user must already be aware of the benefits and would like to know how to use the product to get these benefits. However, the audience of the copywriter would like to know the benefits for using the product so that they can decide whether or not to buy the product. The ability of the copywriter lies in the ease with which the audience is persuaded or convinced to buy the product. The ability of the technical writer lies in the ease with which the audience is able to use the product without getting lost.
Call for action
While a copy calls for the action of buying, the end user documents call for ease of use. Though it is cliched, I'd like to recollect the old marketing saying that the customer is the queen. However, it is difficult for the copywriter to satisfy the customer. The technical writer just needs to help the queen effectively utilize the product and satisfy further. The catch here is that the mantra behind communication for both these fields of writing is to be simple. While there are some complex advertisement copies everywhere, these are very simple to their audience.
This brings us back to the 'audience' part of both forms of communication. Unlike poetry or writing novels, both copywriting and technical writing are directed by the audience and not by their creativity.
