Schmidt’s primary argument is reducible to the need for handling exceptions and the problem of time pressure. He is thinking of the problems facing germany because of the pace and problems of normal political processes.
Authority can assist in those conditions where (a) folly and fashion of the people (b) political processes fail, (c) a people must catch up when behind, (d) attempted takeover of the pollity, (e) warfare.
In all those cases the monarchy has the least bad incentives.(Hoppe)
( fyi: https://en.wikipedia.org/wiki/Carl_Schmitt )