Confusing message on server install

Hello,

While installing the postgresql-12 server package on Debian Buster I see
the following output:
# apt-get install postgresql-12
...
Creating new PostgreSQL cluster 12/main ...
/usr/lib/postgresql/12/bin/initdb -D /var/lib/postgresql/12/main
--auth-local peer --auth-host md5
...
performing post-bootstrap initialization ... ok
syncing data to disk ... ok

Success. You can now start the database server using:

    pg_ctlcluster 12 main start

Ver Cluster Port Status Owner    Data directory              Log file
12  main    5432 down   postgres /var/lib/postgresql/12/main
/var/log/postgresql/postgresql-12-main.log
update-alternatives: using
/usr/share/postgresql/12/man/man1/postmaster.1.gz to provide
/usr/share/man/man1/postmaster.1.gz (postmaster.1.gz) in auto mode
Processing triggers for systemd (241-5) ...
Processing triggers for man-db (2.8.5-2) ...
Processing triggers for libc-bin (2.28-10) ...
root(at)debian10:/home/test# pg_ctlcluster 12 main status
pg_ctl: server is running (PID: 2733)
/usr/lib/postgresql/12/bin/postgres "-D" "/var/lib/postgresql/12/main"
"-c" "config_file=/etc/postgresql/12/main/postgresql.conf"

So I see the message "Success. You can now start the database server
using:", but in fact the server is running.
From my understanding, the original initdb's message like
    /usr/lib/postgresql/12/bin/pg_ctl -D /var/lib/postgresql/12/main -l
logfile start
is substituted with:
    pg_ctlcluster 12 main start
But shouldn't both lines ("Success. You can ..." and the following one)
be suppressed when installing the server from the package?

Best regards,
Alexander