Unless you need, like me, 24-32 GB++ of RAM. Dual HDDs, and a whole lot of cores to run 3-4 VMs at a time.
Then the laptop is so resource-poor that it is rendered useless for the workloads I described in the article.
This article wasn't about how to make a "cheap home server"---it was about replicating real data-center-class hardware in the home and how to do that cheaply.
Granted no ecc, no mirroring, no future expansion. But then no 18$/month power bill either. To each their own.
We don't run 24/7, only when we need to do our experiments.
So the power bill is much lower than what a lot of people are worried about.
This setup is definitely used on-demand :-)