There is a functional down side to having the likes of the Ultraguage attached all the time, right?
Yes, I am quite disturbed by the Govenment Motors management deciding we are too stupid to want gauges. There should be both gauges and lights.
If you are inclined to install a real temperature guage, consider making it an oil temperature guage.
Sadly idiot lights over instrumentation is not exclusive to GM, in fact IMHO GM has been one of the better manufacturer's at providing consistently good gauges (i.e they had more &/or better gauges then say FORD on most of their vehicle lineup).
O.E.M.s make cars to sell to the general populous. They want to make cars as cheap as possible to fluff their bottom line, BUT they've got competition so they have to try to be the most reliable, fastest, best handling, most mpg, flashiest, etc to beat the other O.E.M.s and take their sales.
Improving their cars cost money, so they save where the can. My generation sadly has an extreme obsession with form over function, new is cool regardless if it works (I-phones come to mind).
So what's easy to cut and save money while not affecting many potential buyers? GUAGES!! they don't stream Bluetooth, or have apps so my peers have little use for them. all they need is -Gas, -Speed and well that's really it, oh and they may want to know their MPG.
So in a stroke of brilliant engineering O.E.M.s are wiping out gauges because well only a shrinking portion of buyers want them. Don't blame GM, blame the buyers.