Well, there is a _bit_ of a difference between 'Web App Scanners Miss Half of Vulnerabilities' and 'On average, Web App Scanners Miss Half of Vulnerabilities' especially when NTOSpider picked up a (frankly, amazing) 94%.
However, like accessibility, running any tool then getting green lights and saying "Yep, we're good to go!" is just...naive (trying to be nice here). Tools are helpful for picking up simple things like XSS and file/directory guessing but it in no way substitutes for a real pair of eyes.
Most of the most horrendous webapp holes I've seen would be impossible to find without manual investigation.