The martial arts may have begun as an expedient means to train warriors to fight and hone their skills, to improve their chances of survival and success in battle, but they've long since evolved into something far broader and richer than that.
What unites them all is that they take combat as context, but what they do with that, including how literally they take it, varies widely.
That context provides a framework which renders meaningful what might otherwise be random, pointless movement. If near-term utility is a pressing concern, as for soldiers training for impending deployment, that context can also be a powerful source of motivation.
But even when utility is not an immediate priority, or no priority at all, having such a demanding context can help to focus the mind and drive practice towards perfection. One trains to make one's actions real, to invest them with integrity, as defined by the context, even if one has no expectation of ever using the skills developed in combat.
More importantly, through practicing in this manner, one is brought face-to-face with one's frailties as well as one's strengths, and ultimately with oneself.