one point missed here.... rod blanks have a spine from tip to butt..... location of guide placement "changes" in relation to the spine depending on whether you are building a baitcaster...... or a centerpin/moocher/spinning rod.
Guide spacing also changes, depending on the action of the blank as well. If you are just playin around with an inexpensive rod..... and you don't bust it "fishing it upside down" then why not use a baitcaster with the trigger filed off as a centerpin...... if it works for you...... who cares really.
But... if you are buying an expensive custom or factory rod for that matter..... being able to judge the spine and where the builder put the guides..... is important to many guys. Improperly placed guides in relation to spine is a cause of rod breakage...... improper spacing of guides to distribute load.... is a cause of rod breakage as well.
boring you yet.......