The reasoning behind this is because Windows Update sometimes installs new drivers that may cause compatibility problems with Samsung laptops. The anti-update tool from Samsung loads automatically so many users will be unaware they're no longer getting security updates from Microsoft. Users can manually start and stop this feature in Samsung's bundled bloatware but Windows Update gets disabled again with every reboot.
Samsung’s reasoning goes something like this:Source: Neowin
When you enable Windows updates, it will install the Default Drivers for all the hardware no laptop which may or may not work. For example if there is USB 3.0 on laptop, the ports may not work with the installation of updates. So to prevent this, SW Update tool will prevent the Windows updates.
That may sound shocking to those of you who know that Windows Update is not only responsible for drivers and features, but much more importantly, for critical security updates. And come Windows 10, it will also be responsible for new versions of the OS, as Insiders already know.