What is the purpose of the Immortal trait for custom rulers?

Question

In Europa Universalis 4, one of the options for creating a custom nation with 800 points is to make your current ruler immortal. Yet, in order to do so you must start off with a one province nation with non-western technology, abysmal development values along with the weakest set of national ideas the custom nation designer will allow.

Other than the obvious effect of having your king not able to die throughout the entire playthrough, is there really a legitimate reason for having the ruler immortal, other setting their stats at 6/6/6?

Answer 1

You're correct - guaranteed 6/6/6 is a tremendous boost to the overall development and progress of your nation. No more 0/1/2 heirs that live till 80, you get +3 adm/dip/mil points more every month for 380 years than any other average nation. You can at the same time rush technology in early game and boost development in your starting province. Also keep in mind that you won't get stability hits when ruler dies. This directly translates to more adm points.

Just don't make him a general and beware of rebels that change government type.

Answer 2

You can actually be pretty smart about it and give the ruler traits as infertile, which gives -2 nation-points per trait (so max -4), and you can make your heir Age 0, giving -24 nation-points, you can then give your consort a trait that gives her -2 nation-points. If you choose the right tiles you can have western tech. By setting your government type to the lowest you save another 10 nation points, and if you don't have an issue with sacrificing some monarch-points you can make your ruler 5/5/5, which is still really good and saves you another 14 nation-points. By doing this you can then go to your ideas, pick whichever ones you like that have a base cost of 0.0, and you will be able to buff 2-3 of those to lvl 2.