For an office there are usually several capable people. With an official, it is not as with an artist, whose talent is unique.

Who decides then?

We cannot calculate exactly which of the capable people to take. The link between person and office always remains somewhat a matter of chance. So the power of the crown appoints the official. It is the deciding and sovereign power.

Summary: There are always several suitable people for an office. We cannot derive the choice among them. So the power of the crown appoints the officials.