Because it gives you insight into what your company believes matters and contributes value to the company.
That's all well and good, but managers often have a different incentive structure than normal employees; a manager might command a significantly higher salary, but be out on her ass if her group doesn't meet business performance targets that depend on every member of her group and her own business judgement. An extremely common example in services companies: managers are often responsible for their region's number.
Some of them are, I report to the CIO directly and sit on the Corporate Compliance board of the organization. I care because I think something like that would make more organizations accountable for being reasonable with executive and management pay.