Two times when one may want to underline: 1) Making a citation of a book’s title, according to MLA standards guides, and 2) If needing to make a graphical representation of a web page with hyperlinks underlined. While some web pages don’t do this and many people disable this in their browsers, to much of the general populace, underlined text means “hyperlink”.
There may be other examples, too, but those come immediately to mind. I’m not saying it should or shouldn’t be offered in AE; I’m just noting two situations where a bigger font or italics might not be a better option.
The real reason is that Adobe doesn’t care about wasting people’s time. Creating a line to underline text takes 10x longer and doesn’t move with the text. It’s a stupid, thoughtless mistake, much like the haphazard choice of keyshorts across Adobe software. Inconsistent, stupid, lazy choices are made by incompetent Adobe employees everyday, and the lack of underlining is just one more example of this. I spend a lot of money on your programs, and stupid little decisions like this eat up my day and cause a great deal of wasted time… which is very valuable.
I joke, but you guys are doing a great job. Please don’t think of your work as a waste of time! Just because something’s difficult, doesn’t mean it’s not worth doing. Accomplishing the worthwhile goal of underlined type would help your team build confidence in yourselves, and contribute to a pattern of success that other Adobe employees might be inspired by. This small gesture may help the entire company come together and resolve, for example, the inconsistent keyboard shortcuts. The team working on Illustrator might be inspired to adopt Command-i to import files. Wouldn’t that be something! Then the team over at InDesign might do the same. If both those groups do it, realizing that it makes sense to have consistency among programs that are designed to work together, maybe the team at Flash might realize that Command-r is a stupid keyboard shortcut for importing files and also adopt command-i. It could all begin by proving that the After Effects team aren’t just a group of time wasters waiting for people to suggest useful features, and have some initiative. I have confidence in the After Effects team. I’ve been using your software for 20 years, back when it was created by CoSA. Now those guys really created something special! I know it has been slowly improved over the years, but don’t stop now. After all, it could revolutionize the entire Adobe corporation… and possibly, the world.