In our case we do (eventually) integrate the techniques of standalone uninstallers into the products. But having a standlone utility allows us to make changes and fixes to the uninstall procedure of different vendors and versions more quickly than depending on a full fledged product release. Specifically in the case of CloudAV the product itself simply calls to stop the service but this sometimes doesn't respond in time or at all. So we released a generic uninstaller that kills the service if this happens with a more brute-force approach. Eventually we will either (a) fix the service response time during normal uninstall or (b) integrate the service-stopping technique into the products' uninstall functionality. In short, a standalone util allows us to implement new techniques and fixes quicker than relying only on big product releases. But these improvements always end up eventually in the product.