[Dan Moran] “As long as you are happy with the picture on the screen then don’t worry about anything else”
If only that was true… 
You probably mean, “as long as you are happy with the picture on the characterized and calibrated 709 screen…”?
Otherwise, clients… feel free to point at the sRGB preview in the UI and say “I want it to look like that…”
But underlying all this is the total anarchy and confusion that desktop video publishing has wrought in the name of democracy when any manufacturer feels utterly free to defy SMPTE, CCIR, et al., and persons unfamiliar with the environment then run around in a panic thinking, I gotta have a LUT, I gotta have a colorspace, I gotta have a screen calibrator that is meant for another industry, “but it says it does what I want” … errrr, but it doesn’t, and so it goes.
But in confusion lies opportunity… like, say… Egypt. or Syria… or, quite a list, actually. Mali, anyone?
jPO
“I always pass on free advice — its never of any use to me” Oscar Wilde.