The original purpose of punctuation (and formatting, at least experimentally) is to provide a means of reproducing a writer’s thoughts accurately enough in the reader’s mind that they can share the concept. This is quite distinct of the playwright’s desire to provide the framework for the actor and director, a format that contains notes and suggestions rather than absolute descriptions or injunctions of behaviour.
In print, the formatting conventions were to aid and complement the way reading is taught — to allow the reading to become as effortless and “invisible” as possible, in order to allow the reader to inhabit the story. Authorial changes, the uneducated choices of typesetting and format, the abandonment of conventions all destroy the purpose with no thought of its origins. I buy printed books, new and secondhand, and slowly encroaching into the traditionally published domains are the same changes.