The Windows 10 Update Assistant enables users to upgrade Windows 10 to the latest builds. Thus, you can update Windows to the latest version with that utility without waiting for an automatic update. However, the Update Assistant is hardly essential as the updates will eventually roll out to you without it.

Should I use Windows Update assistant?

Windows 10 Update Assistant is meant to ensure users deploy the latest Microsoft Windows updates that they might miss or choose not to apply, which can lead to vulnerabilities. It provides push notifications that inform the desktop user of any updates he has not yet added.

Is it OK to uninstall Windows 10 Update assistant?

So, yes, you are quite right to uninstall Update Assistant in Settings > Apps > Apps & Features. It is not needed any further, or ever really.