Realistically though, in what situation would you find yourself in a situation where a street fight would occur and you have no choice but to protect yourself? I would argue that 99% of "street fights" are situations you can easily avoid if you keep your ego in check and simply walk away, or if you don't frequent certain areas like bars or pubs. That 1% is when you're dealing with an unhinged person who simply won't allow you to escape. Challenge fights fall into that category as well where 9/10 times you can simply walk away from the situation and let the person say whatever they want.
Unless you're a soldier, "Battlefield" isn't going to apply, but even if you are a soldier, chances are you're using weapons, and you're not running around the place with your shirt off looking to fight someone hand to hand.
Frankly. the most likely situation where you're going to apply martial arts training is police work, security, and similar lines of work. I would add being a teacher to that list, since some schools are pretty much havens for violence, and I've seen plenty of instances where teachers had to fight off crazed teenagers who are often bigger and stronger.