As a WordPress web developer you definitely encountered at least one of the following situations:
Did you ever customize a plugin to fit the theme and you wanted to keep the customizations during theme and plugin updates?
Did you ever “just want to try this quickly” and you didn’t feel like digging into the theme’s files and then upload them with FTP?
Did you ever need to get your customer’s or co-worker’s approval for changes before you make the changes live?
Did you ever want to add custom CSS or JS only on specific pages?