WSA as stand-a-alone vs companion anti-malware solution - Change in marketing

Prevx then Webroot/Prevx used to use as one of its major marketing features that the product was compatible with and could be used along side most any other A/V product.
 
As the years have passed since Prevx became part of Webroot and WSA has matured into an established stand-alone-anti-malware solution, I see very little mention of compatabilty in marketing the product.You have to look hard to find it and Webroot used to have a listing of known compatable products on its's website.
 
Is this just a marketing strategy based upon WSA having been developed into a mature "Top-Shelf" stand-alone-product or is there something that has been done to the program somewhere along its development timeline that has made it less compatible with other products? Is it now more likely to slow down your PC or web browsing if used as a companion product?
 
I hear differing views over at Wilders. Many still use it as a companion product, but more and more posters are using it as their sole anti-malware solution.