Signwriting, signs and signage are all wide ranging, generic terms that can be used to refer to ALL and ANY type of sign.
Originally signwriting referred to the art of 'writing' a sign which was done by a skilled or trained “artist' or 'sign writer'. This work was done by hand, took a long time and required skilled and trained individuals. This changed with the introduction of computers into the sign industry. While the task of vinyl application still requires some skill and training, the design side which required the artistic skill has now been moved to the computer designer and operator. Today even the skill of vinyl application is fading out as more and better direct to media printers enter the market.