Conversion rate results also influence ROI from every traffic source and campaign you run; so the higher your conversion rate, the better your ROI will be.
CRO improves nearly every other aspect of digital marketing by increasing the value of your website to each visitor. The continuous change is due to permanent improvements within your CRO and it lasts long after testing is complete. This way, even if you decided to build a whole new website four years from today, you would still retain and be able to use the results from all tests that were run now. The information would still be a knowledge bank of optimal practices useful for your next venture.