[dannyw]

Fun and learning is a really good reason. It also reminds me of the damascene: trying to achieve something that doesn't feel possible, and working through all the extreme resource-constrained engineering limits.

I think most of my embedded projects aren't that useful, but they've taught me a lot.

[skippyfish]

I'm not disagreeing with you, I think this goes beyond impractical, it's doomed from the get go.

In my book, impractical means "I built a cuckoo wristwatch". Beyond impractical: "I built a cuckoo wristwatch but there was no room for a working mechanism".

[rufasterisco]

I don't see the relationship between "fun and learning" and "(beyond) impractical".

I enter most of my learning project from the assumption that I could just buy/install whatever I am building and save time/money.

Please consider seeing things from a different perspective than "your book".

Not saying this to antagonise you, but because a lot of time reading comments like this makes other posters less willing to share their impractical efforts, and would love to read more of those, not less.

[dannyw]

Learning how to make a cuckoo wristwatch and everything that involves helps you acquire skills, even if what you build is fundamentally useless.