but if you can come up with another reason I'd certainly be interested in learning it. Its my understanding that of the rought 1,200 Daytonas built approximately a little over 400 had plexi. As of this point in time some owners of each style have converted their cars to the other look, sometimes following an accident, other times just liking its looks.
I am not sure why the E-Types lost their covers, I heard rumours or concerns of them having water leak into them, fogging up and being less effective...not sure if thats true. However, It wasn't just in the USA that E-Types lost their headlamp covers. All E-Types world wide lost their covered lamps at the same time. Some brief research I did indicated that some of the last of the Series 1 cars, unofficially sometimes called the Series 1.5 cars, had open headlamps.
The Daytonas were released in 1968 after Jag had given up on covered headlamp E-Types. I'm not aware of the Ferraris having rumours of leaks or condensation in their plexi glassed cars. If you find some more definitive info regarding th reason for the different lamps let us know.