If you measure something, it costs in clock cycles and memory used.  While people say that EE is more efficient than a server side SQL Profiler Trace, I find there's not really much difference especially if someone forgets to turn the damned thing off.  Also, as Eric suggested above, even if something isn't used, there may be some forgotten job somewhere that really serves no purpose.  One does require some bit of esoteric knowledge of such things to either prevent something valuable from being turned off or, to reverse it all, something that is being used that actually provides no value from being turned off.