if, like me, you live with someone who is not 'techie' a screensaver serves one useful purpose [and quite possibly an original one as opposed to just power down the monitor] which is to remind that user:

a] that the machine is still powered
b] that it should be shut down properly before it is switched off at the main

but it does not have to be 'pretty' agreed

Actually I have had some very good ideas occur whilst gazing at screensavers as well as open fires, sunsets, horizons, and simply out of the window - maybe that's just me...