In the Russell days, they referred to dedication as consecration. The present JW folderol of 'dedication and baptism' consists of studying through doctrinal books, answering questions on the creed/beliefs to the satisfaction of examiners, 'dedicating' to God (the only part of this which is private), official baptism in public with the date recorded permanently, and later the added baptism vow containing verbiage to identify as a JW in association with the WT religion.
I maintain that this constructed process was invented primarily for legal reasons to prove in court that a person was a practicing JW. This came up in the Rutherford and associates 1918 trial where men were claiming to be members of the faith and exempt from the draft, but the WT didn't have a way to substantiate their claims. It's part of what landed Rutherford in jail in 1918. Back then it was all about the draft.