I would agree in theory that when designing a new sealed led light that this would be the way to go,(i would have to run many tests before doing a run of circuit boards with this type of circuit) but as far as running leds on a string or in a pinball machine i will stick to the method i have used for years.
The reason why i stick to this in a pinball is because it is not practical to re wire every lighting circuit in a pin.
The reason why i stick to this with leds on a string is because in every application that was bought off the company i worked for the customer would order x meters of led string lighting and cut it to the lengths that were required and connect it to a power supply. in most applications they would not even use all the leds. so if the leds where wired in series there would be a great chance that the leds would be cut half way through one of the series.
there are other problems you run into when running long lengths of cable with leds in commercial applications which you only learn through many tests.

any way i have had fun with this discussion fire power  

I will finish my last post on this thread regarding using current regulation for leds. How many of you seen led traffic lights with large ammounts of the leds out? I have seen many of them, the power supply on these led fittings are current regulated.