My $0.05 the alert can be multi line so a more comprehensive message.
(alert "The drawing must be converted first.\n \nWill now exit \nFix then rerun")
You can also display a slide, Vslide, that can have a lot more detail and images etc, the slide sits there till you press enter.
Another I have is for prompts it displays a message that has a timer so it closes without user input. "Please pick the sq objects"