Why is laser alignment particularly beneficial for long spans?

Laser alignment is particularly beneficial for long spans because it avoids issues like bar sag. When aligning machinery over longer distances, traditional methods using straight edges or dial indicators can be affected by the physical characteristics of the tools themselves, such as bending or sagging due to their own weight. This can lead to inaccuracies in the alignment process.

Laser systems, on the other hand, project a straight line over long distances without being affected by gravity in the same way. This means that the accuracy of the alignment is maintained regardless of the span length, thereby ensuring that the machinery operates properly and reduces the risk of wear and tear on components due to misalignment. As a result, using laser alignment is especially advantageous in long-span applications, where precision is critical to the system's performance.

The other choices, while they may seem relevant in different contexts, do not specifically address the unique challenges presented by long spans in alignment tasks.