Define useful.

Will any martial art make it a good idea to engage in a street fight, ever? Will any martial art prevent you from getting shot, stabbed, or ganged up on and beaten? No. Your best bet is situational awareness and a keen sense of GTFO.

However, martial arts are physical activities. They involve precise movements, and allow you a safe space to build conditioning. All of that means that, even if the techniques of the specific art you practice are fundamentally useless in the situation, you’re going to be just better able to use your body effectively. Hopefully to run.

I’d say the biggest thing a martial art has over a traditional sport is conditioning yourself to take a proper hit. Beyond any technique, the first hit is usually the deciding hit in a street fight. Knowing what it’s like to be hit, and being able to not immediately crumble, go further than any technique.