It can be useful, but only in the off chance that they're of different genders. But all this is at the expense of canonically having assigned genders to nouns, which the speaker has no way to compute or derive. In other words, even if I know the very word I want to utter, I can't legally form the correct sentence until I know its gender. All things considered, to me, the cost outweighs the benefits.
> even if I know the very word I want to utter
The gender is part of the word. If you don’t know the gender, then no, you don’t know the word.
There is no way to compute that “dog” begins with the letter “d”, even if you know that the remainder is “og”. So should we ban words that begin with “d”? Of course not. In German you must memorize “der Hund”, not just “Hund”, just like in English you must memorize “dog”, not “_og with unspecified first letter”.