You may not be able to change directions for close to a year, so time stretches interminably while you wander. Career goals aren't as fixed as trees, and will likely move farther away when you wander off track. Trees can shelter a large number of Boy Scouts, but many career goals fixate on a single desk in a corner office. Getting there late because of a detour could be worse than never getting there at all. The second problem that comes with lacking a career line, the inability to overcome obstacles, may be even worse than wandering around.
People lose sight of their goals, then self-destruct when they hit an obstacle.
The obstacle overwhelms their ability to see anything except the obstacle, and they fold or commit career suicide. Their career line disappears. Your career line forces your career journey to continue in the right direction. Since you have a goal, you may as well get there the quickest and easiest way possible. Follow a straight line, defined by at least two points.