On the status report, if you have uninstalled the Update module you will get a big scary warning:
Update notifications are not enabled. It is highly recommended that you enable the Update Manager module...
There are many situations where it's perfectly reasonable to disable the update module, such as in an enterprise environment where you monitor for updates via other dedicated means and don't want the performance impact of having Update enabled in production. In these cases, the warning is just a distraction and contributes to a "crying wolf" mentality.
Ideally, there would be a way for expert administrators to disable this warning.