With sales, you want to pay for performance and pay for outcomes. And with sales, it's easy to measure quantitatively and simply. Good sales people love it and make good money—bad sales people don't get paid and/or leave.
This is the ideal world. As a employer and an employee, you wish all your departments could be measured and rewarded like that.
Not everyone is cut out for sales, and that's fine, but the model works and works well. Examples where it doesn't work well (e.g., over-promising, over-paid) are companies that have poorly balanced incentive commission plans.
[1] https://www.nasp.com/article/FF282761-5D6C/sales-is-the-high...