One of the original reasons for secrecy is that members are given key words, signs and tokens, to provide to the angels who stand as sentinels.
My conjecture for the tokens, etc is this. While the restoration was being deployed on the Earth, a complementary security system was being deployed (wherever it is that sentinel angels do their thing). Since an accurate reading of human hearts is notoriously difficult, the keywords, signs and tokens were a stopgap measure. It was put in place to give the sentinel angels time to be properly trained in discerning who was who. This strikes me as a mid-level manager solution but Joseph seemed to have connections all up and down the heavenly sphere.
If my theory holds, the security tokens should be done away with at at future date. In the mean time, the c-suites are maintaining them for stability's sake.