When somebody brings up DDG's bangs, someone else will often chime in "yeah, but you can make your own in browsers so who cares?" That was often my response.

But the fact that there are community-maintained bangs is really nice. Bangs for all kinds of websites I probably wouldn't have made, but there they are. And since I'm often jumping on new computers, I don't need to bring/import my preferences. Just change the browser's search to DDG, then all my known bangs (and unknown!) are there.

I don't think that's the best criticism of bangs. The best criticism is that your query already gives you what you want if you just type it into Google without the bang.