This sometimes works, but I've found quite a lot of cases where it doesn't. The two most frequent culprits for me:
1) Smaller index. Some stuff just seems not to be in DDG at all. Even after finding a page I'm looking for via !g, I'll go back and try to see whether I could've gotten DDG to return it with some more specific search term (even verbatim phrases from the page) with no luck.
2) Languages other than English. The Google/DDG search quality gap is much, much larger in Greek than in English, for example.
1) Smaller index. Some stuff just seems not to be in DDG at all. Even after finding a page I'm looking for via !g, I'll go back and try to see whether I could've gotten DDG to return it with some more specific search term (even verbatim phrases from the page) with no luck.
2) Languages other than English. The Google/DDG search quality gap is much, much larger in Greek than in English, for example.