Question

why is publishing needed in flash​

Answer 1

Flash converts your movie data into a highly compact and efficient form in an SWF file; the SWF file contains only the information needed for playback of your movies. In contrast, when you save your movies by choosing File➪Save (or File➪ Save As), they are saved.

Answer 2

Flash publishes your movie to an . swf file, creates the appropriate HTML file, and opens the HTML file in your default browser. Viewing your Flash Player file in a browser reveals how the browser will display the movie when you upload it to a Web site.