This system defines its base units in terms of the planck units which is a (as far as we currently know) fundamental system of units
the time system is defined in such a way as to have it line up with a day such that 1zt (or 216t) is equivalent to 1day
the distance system ends up being a nice in-between for metric and imperial
1d
1hd = 24d
1zd = 216d