1) Benefits from broad experience
2) Solves problems and doesn’t create new ones
3) Pays for itself
For the past five years I've been responsible for nearly every aspect of web production on over 100 websites. With the perspective of a project manager, I look at websites and see all the moving parts.
As a web producer, every decision I make is informed by that global view. And the result is my ability to dependably make websites more effective.
If your business depends on your website then you need a minimum level of professional quality assurance on many fronts. Build quality, lead generation, usability, SEO, and content use, all play vital roles in the success of a website.
Running QA on over 100 websites, I know all the places to look for problems and ensure that issues get addressed.
Cost / Benefit
Low-cost websites are a dangerous honey pot. Most often, low-cost work cuts corners that negatively impact performance. If the net result is lost revenue, then your "cheap" website is costing you a lot more than what you paid for it.
Professionally produced websites should pay for themselves. The alternative may simply not work.