My take on it is that DotNet is a set of build blocks / methods that software developers can use / access in their applications in order to avoid developing everything from scratch themselves.
So in instances where software applications (that you use) have been built to use DotNet, if you were to uninstall DotNet those appications would cease to function.
In any event, it sounds like what you are describing is not the installed DotNet but a download (of an installer?). You say it is in Downloads, but what is the full path (e.g. C:\Users\Largo\Downloads)?