The point is that with DDG, you have a uniform syntax for searching multiple services that doesn't require any special cooperation from your browser or those services, doesn't require any setup apart from using DDG and only requires you to learn one new concept.

And this will work anywhere where webpages work (like, say, lynx), and will work consistently. There are thousands of !bangs, from things ranging from amazon, to wikipedia, to maps, to dictionary definitions... You aren't limited to a handful of hand picked services that your browser decided to support out of the box, or that you decided to manually configure.

Also, there is generally decent support to switch languages and regions for services that support it. For example, "!w" gets you "wikipedia", "!wsimple" gets you the "Simple English" version and "!wpt" gets you the Portuguese version.

IMHO, this is all extremely convenient.