I thought it made my life easier by adding the environment variables.
Adding environment variables was a good thing for saving the typist's time.
When starting PostgreSQL, instead of using:
/usr/local/pgsql/bin/pg_ctl -D /usr/local/pgsql/data -l logfile start
(69 characters including spaces)
pg_ctl -D /usr/local/pgsql/data -l logfile start
(48 characters including spaces)
[(69-48)/69*100]% = 30.4%
The number of characters decreased by 30.4% after adding the environment variables!
This meant less confusion when a human being read the line.