All this complexity to save a few bucks per year on your electricity bill? This is ridiculous, the Pi costs far more than what you can be expected to save.
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Anyway it's not about the money for me it's any the aesthetics. Burning power for nothing is yucky.
Edit: just been Googling around. OP is running one of these HP mini PCs. They are pretty efficient! Some go well below 10W. So yeah I would say for the specific use case it's unlikely to matter very much. But still it's a useful thing to be able to do in general.
(I also heard that it sometimes suggests power saving modes that are usually switched off for a good reason, like apparently you really don't want some USB controllers going into certain sleep modes as they take seconds to come back).
Looking at powertop, the various qemu virtual machines have high events/sec compared to host processes. There are also a couple of timers - tick_nohz_handler and hrtimer_wakeup - which seem to generate hundreds of events per second.