Yes yes, I know that. 
You can do all MB searches in Firefox, even more complex searches involving JavaScript* in Firefox, Vivaldi, Opera.
So the possibilities are without limits.
But as I use several browsers and computers, this duckduckgo !bang thing was very welcome to save setting up all this all the time everywhere, especially on smartphone, where it is less possible.
* Although www.minc.gr.jp/db/ catalogue number search doesn’t require this any more.