Could 'Terminator Zones' on Far Off Planets Harbor Life?

There is a small chapter in Blue Mars by Kim Stanley Robinson where he depicts a train-like city moving along the terminator zone on Mercury (which rotates around its own axis very slowly).

Dunno, the earth often has a 140F degree range across it's surface, hell often 100F or so at the same point just different latitudes between 0 and 35,000 feet.

Doesn't seem that different for a tidally locked planet, sure the variation would be higher, but if the planet average is 60F (earth is 57F) being tidally locked doesn't seem like a death sentence, doubly so for aquatic life. Sure the most diverse areas might have large bodies of water nearby to help mitigate the swings, or be in canyons/near mountain ranges to avoid direct blasts of crazy hot or cold air.

I'd worry about all the water ending up on the cold side, but if dry enough sublimation would take over the water cycle.

I think of Niven's "Known Space" series where they sent out interstellar probes to look for habitable places and found a bunch of planets that only had habitable spots, such as

https://larryniven.fandom.com/wiki/Plateau