Personally doing something like this, except not from scratch, but a major renovation.

I'm not using concrete at all, I am reusing foundations, and mostly sustainable domestic wood and other recycled materials. I've been taught from a fairly young age about carpentry so I'm not ultra-green and I do use some local tradesmen, which I'm learning a lot from. I plan to do some more of my own projects so it's been great to work with them and gain more insights into how they work.

I've learned an incredible amount, there is something ultra inspiring and rewarding for me when working with physical material. I find it sort of unlocks parts of my brain I forgot I had. Working in the third dimension I guess?

Also, remember all that math you learned in school but hardly use? Well you'll likely be revisiting at least some of it! Which feels awesome.

Regarding the time management, project management etc, it's true, you have to learn all this, but more importantly you start to have to learn to compromise and really get good at communicating with people. A mistake in the physical world can get costly very fast.