It matters because judging channels in isolation misleads you. A channel that never gets the final click may be what introduced the customer, and cutting it would quietly hurt the ones that close. Attribution tries to value the whole journey, not just the last step.
It's genuinely hard, and privacy changes have made tracking harder, so no model is perfect. The practical approach is to use attribution as a guide alongside common sense, rather than treating any single number as the full truth of what drove a sale.
Updated July 2026