I think its because this is a hobby project and for a lot of people the cheaper a hobby project is the more they can keep running before the money runs out. It's also that for some people optimizing costs and making things run on as few resources as possible is fun.
But if you don't find it fun spending time performance optimizing to the extreme, and can afford it, then there's nothing quite like massively over-provisioning hardware. It makes a lot of performance and reliability problems go away.
Probably some truth to all you said. I spend way more money on my hobbies.
For this creator, his hobby is well into the realm of "could productize some component", even if just creating derivatives of this for some commercial purpose. I'd much rather spend time on that than the optimization part. My thought is HN has skewed more technical than entrepreneur over the years and the folks who are into the optimizations are more vocal in the thread. Could also just be the cohort of HN that was attracted to this article. "Send push notifications to your phone" sounds pretty technical. Or, the tech recession is changing mood about money and I'm not in tech.
But if you don't find it fun spending time performance optimizing to the extreme, and can afford it, then there's nothing quite like massively over-provisioning hardware. It makes a lot of performance and reliability problems go away.