If you're fired for doing something bad, then you become ineligible for unemployment compensation (which is something you earned) and some other benefits. This creates a perverse incentive to claim a cause for termination. On the other hand, it also creates an incentive for the fired employee to sue, especially if they think that the employer didn't have an utterly bulletproof paper trail and discipline procedures.

For this reason, it's sometimes more practical for a company to terminate someone without cause, and just pay out the benefits as a cost of doing business. They can wait for a slow season, when they would normally shed some workers, and terminate the lowest performers.

Companies avoid the term "layoff" because it has connotations, such as eligibility to be re-hired when conditions improve. So they use "reduction in force" instead. The people who are fired are "impacted," and so forth.

The terminology used doesn't mean anything... what matters is whether someone was terminated "with cause" or not.