Not to mention that an app for an extremely narrow set of needs will probably have a simpler, more intuitive UI. With a complex application, it's easy for users

Not to mention that an app for an extremely narrow set of needs will probably have a simpler, more intuitive UI. With a complex application, it's easy for users to not even realize a feature is available. For example, did you know Word 2007 can generate "Lorem Ipsum" filler paragraphs for you automatically? Most people, myself included, are more likely to go to http://lipsum.lipsum.com/ http://lipsum.lipsum.com/ whenever we need filler text, even when we have Word open and running.