Yaris, Scion xD, Honda Fit - no water temp gauge

I've been thinking about what my next commute car is going to be. 80
miles/day, it's just me and my briefcase, so thinking of a small
vehicle with great gas mileage. Yaris hatchback, Scion xD, or Honda
Fit would work for me. Problem is, none of them has a water temp
gauge, just an "idiot light."

Would you consider buying a car (brand new) that only has the water
temp "idiot light", but no water temp _gauge_ ?

Btw, do these "idiot lights" come on early enough to prevent major
engine damage, or only after the engine has overheated to the point
where the head gasket is blown?

Also, the next bigger models that do have the water temp gauge would
be Toyota Corolla, Matrix, or Honda Civic. But the extra purchase/
ownership cost may not even offset the possible repair costs resulting
from a Yaris/Fit/xD engine overheating (which, if happens, would be
several years down the road.)

TIA,
Bubba