Does Postgresql need initial database initialization?

Question

PostgreSQL

Judging by the instructions, after installing the DBMS, you need to start the database cluster to initialize it .
initdb -D /usr/local/pgsql/data
But if there is a line in the postgresql.conf file
data_directory = '/usr/local/pgsql/data' i.e. If I understand correctly, here the DBMS will look for the database files at startup.
Is the initdb command necessary?