If I want Google results, it's a heck of a lot faster, easier, and natural to just Google it instead of adding some kind of search operator BS to my query. I used DDG for a while (a long time ago, admittedly) and basically had to !g every query I ran in order to get acceptable results. In the end, I gave up because it was just adding typing and thinking time to search.
I suppose one could argue that the interface lacks some of the annoyances of Google, but I feel like quality and speed are the most desirable traits of a search engine (in that order). If we're just using somebody else's results anyway then why should we accept a slowdown?
I like the !bang operators because I can get results from Google for specialty searches like maps (!m) and images (!i) right from the address bar in Chrome, but still keep DDG as my primary search engine. Google's results are slightly better, but it hasn't been a big deal for me. I still end up finding what I am looking for.