Very interesting ideas. I read this as a perspective possibility as far back is 20 years ago, during a nerdout phase where I was setting up a science fiction game. The idea has always really intrigued me, that there can be a planet where there's this narrow band of habitability scorching death heat of the sunglasses side and the infinite coldness of the dark side

Imagine the science fiction distant future where we could live on such a world, you live in a city that's quite comfortable, but if you go to one side of the extremes of the city the temperature drops 10°, and the other side it raises 10 degrees. While 10 kilometers inone direction and your at a pleasantly hot artificial beach, but 10 km the other way you can go skiing.

Kinda sweet :)

If simple life is as common as I would like to believe it is, I suspect there are many primitive organisms who are surviving on such environments. Not as convinced that such an environment would be well suited to the development of advanced life, but maybe I mean at the end of the day, we really have no idea.

But it's fun to think about