You really can't use "we promise we won't misuse the information" as an argument, that's what everyone says whether it's true or not, and the whole point of using a privacy-centric browser is that as a user you can't trust those kinds of promises.
They’re primarily a search engine, so yes, you definitely have to trust that they won’t misuse information about what search terms you are querying for.
I suppose that's valid. This is the first time I had heard that DDG has a browser too, and I was just assuming that anyone who would use the browser probably also uses the search engine, which they obviously have to trust when they send search queries to it.
By the way how DDG spend money on the ads like at bus stop, I already starting to NOT trust them. Spend the money on development of development of products.