"Nothing could be more important to my salvation than to find out whether or not Joseph Smith was a liar."
Because if he is, then I'm wasting my time and my happiness in this life, being enslaved in Mormonism. If the other Christians are right, I could be seriously off the path and possibly screwing up my eternities. If there is no God or afterlife, there is no way I want this only life destroyed by Mormonism.
Nothing is more important than knowing if this religion is a lie and all these "unimportant" things are evidences to whether or not the founder is a liar.
THERE AIN'T NO SUCH THING AS "SALVATION"!! Forgive me for shouting but the whole concept and doctrine of salvation is a fairytale of the first order. Once you have that fact firmly planted in mind everything else makes more sense.