It looks like instinct
A runner breaks for second, the throw is a beat late, and the broadcast calls it a great jump. That framing makes the moment sound spontaneous, a flash of nerve at the right instant. It undersells what actually happened, which was usually the product of hours of preparation compressed into a single decision.
Good base runners study a pitcher's delivery for tells — a shift in weight, a slightly longer pause — that signal whether he is about to throw home or to first base. By the time the runner breaks, he is not gambling; he is executing a read he has practised against film of that specific pitcher.
Value beyond the stolen base
The stolen base total is the most visible measure of the skill and probably the least complete one. Taking an extra base on a routine hit, forcing a rushed throw that becomes an error, or simply threatening enough to distract a pitcher's attention all matter without ever showing up in that column.
Some of the most effective base runners in the sport steal relatively few bases, because pitchers and catchers alter their behaviour just from the threat, conceding an advantage before a play is even attempted.
A coached skill
Because it looks improvised, base running is sometimes treated as a natural gift rather than a taught one. In practice it is drilled like anything else, with staff dedicated to reviewing pitcher tendencies and runners rehearsing leads and reads the way hitters rehearse swings.
That is worth keeping in mind whenever a broadcast praises a runner's instincts. The instinct is real, but it was built, and the building is usually the more interesting part of the story.