Waves, wind, sail set, tell tails, wheel/tiller pressure, sun, stars - it really is easy to sail straight in good visibility without your head buried in a compass. I don't consider wobbling around +/-10* or riding lifts and falling off headers as not straight - windvanes do that.
I agree that one needs to consult a compass once in a while as a basic navigation check, but not very often.
Frankly I am surprised at the surprise over this. On certain boats with lots of feedback (our old one, for example), I can sail straight without paying any attention at all to the steering or course.
Surely this is the case for others too?
Mark