The point of creating adaptive sites is to create functional (and hopefully optimal) user experiences for a growing number of web-enabled devices and contexts. It’s not because it’s “the right thing to do”. It’s not because it’s fun. It’s not because it’s trendy. It’s not so you can impress your boss by resizing a browser window.
Brad Frost, once again hitting the nail on the head. The “responsive” trend parallels the “CSS-based layout” trend of years ago in that this isn’t so much a trend but a shift in how websites are built. At the end of the day, making an adaptive website doesn’t have to be a dog and pony show with fifteen media queries that break the content at every 100 pixels. It does, however, need to be thoughtful in how it shifts content for different contexts or devices.