Any reasonably successful business person would have a respectable answer for this question. Their answer may relate to themselves personally ("makes my job easier", "greater personal success", etc) or to the welfare of their company as a whole ("successfully meeting our goals", "helps building our brand", etc) but I am not convinced most people understand how to successfully (and intentionally) align the organization for short term gain and long term sustainable success.
Establishing effective alignment starts with a well constructed strategy that has been vetted by the (SLT) senior leadership team (and BOD if it applies) that can be understood by every employee in the organization. The SLT must be in consensus on the strategy and should revisit it at regular intervals to assess progress, performance, and make adjustments as needed. I consider this a "living" document that adapts to the business environment without compromising the intended meaning.
The vehicle for laying out the moving parts of the strategy is established through communication - written and verbal. This is a two way street in the form of providing direction as well as receiving feedback from all levels of your organization. In too many companies there exists this perception that all necessary information will magically flow to the people who require it but reality suggests otherwise. Good intentions are not enough - the SLT needs to clearly communicate direction, expectations, and goals to the next level down and this should continue all the way to the individual contributor. The feedback component is the tricky part. Real-time information is critical for making sound decisions and solving business problems - this only comes if your company leaders have built strong trusting relationships with their people who hold much of the information.
Cross functional challenges (typically at the department level) almost always occur due to conflicting priorities. Sure, one department head may consider the actions of another department head as divisive or damaging but my experience typically points to issues related to goal alignment. Referring back to the paragraph above, if goals are not "communicated" well, and keeping in alignment with the bigger strategy, divergence in thinking, priorities, and agendas occurs. And it only takes a little divergence at the top to evolve into more serious issues at the lower levels. This is usually when I am called in to "fix" the problem.
Employees in your organization make hundreds of decisions every day and all should be well aligned to your stated strategy. Some are more important than others but the question should be "how many were bad decisions and what did they cost the company". Granted, I am an advocate of the motto "just make a decision" because a non-decision can be far more damaging but you have to stop and think that an increase (even marginal) in good decisions will only help make your company a better and more profitable place to work. Well informed and aligned employees will make better decisions - period.
"We are great at setting direction but lousy at the execution piece". I hear this statement more often than you would think and it has plenty to do with discipline issues within senior leadership ranks however if the organization is not well aligned from top to bottom execution suffers greatly which may have less to do with discipline. Reflecting on the car analogy above, this misalignment causes distraction and results in company leaders putting our fires rather than executing on their strategic plans