It is important as we have plenty of christian groups - each claiming it is right in God's sight .Once the timeline is established we can see clearly God's salvation plan for our times.
8 BC - 7 BC - 3 BC - 2 BC - 29 AD - 33 AD - 36 AD has its reflection in 1878 AD-1879 AD-1883 AD-1884 AD-1914 AD-1918 AD-1921 AD.
Only one christian group fits this timeline : the International Bible Students . And then we look for which next christian organization is its legitimate extension .Jehovah's Witnesses ! They hold on to the name Watchtower that is linked to the year 1879 AD.