One of the big advantages of DDG's bangs is that you don't have to re-type/paste the whole search query. Instead, you click the search bar in DDG, type `<space>!g<enter>`. That's vastly simpler and faster than re-typing the query, then `<space>!g<enter>`.

One of the thing that I miss from Chrome from a while ago is the integration with Google. I remember that Chrome would show the query in the omnibar (on mobile anyway) when doing a search on Google. So if you needed to make changes to the query, you can continue doing so within the omnibar.

I think if we can get something like that Chrome feature in Firefox but for DDG (or maybe any search engine?), using Firefox's smart keywords feature would be a lot simpler, and you can bypass the extra request to DDG that it would otherwise take.