I started out doing that, but I've found myself using !g less and less recently. There are two main things I find myself needing it for: Location based queries, Google will always prioritize UK based results, and often London based results for me. The other is technical searches, I'm not sure how much this is due to Google having better search algorithms for this, or just that it has the data to know that I'm a programmer, but it it's more likely to know that I'm talking about coding with a term like Python or Ruby which could mean something else.
I hope DDG can keep improving, and I do feel like it's a worthy alternative now. I do wonder how they can keep making money with no advertising or paid services, but if they were to be bought out by a big player, I think they would quickly lose much of their user base.