I did exactly the same thing. Why, with just a few dozen hours of hard work, I could probably slice 10% off my $150 a month server bill! And it would make pretty graphs and take cool algorithms and be so much cooler than A/B testing button colors even if that would be about 20 times more effective per unit of effort.

My job as a business owner is to ruthlessly soulcrush the engineer in me some days.

Yes there is: if you have work to be done with a low priority and no deadline, it's perfect.

For example, I bet the EC2 bill would be cheaper than my electric bill if I wanted to run SETI@home on a bunch of instances when it dropped below a certain mark.

The tech didn't exist 2 weeks ago, but now that it does there is a whole class of problems that can be solved more easily.