Any difference between commit/rollback when only temp tables and \copy are used

I have a psql script that obtains data via the \copy command and loads it into a temporary table.  Additional work is performed possibly generating additional temporary tables but never any "real" tables.  Then the script outputs, either to stdout or via \copy, the results.

Does it matter whether I issue a ROLLBACK or a COMMIT at the of the transaction?  More basically: does it matter whether I issue a BEGIN?

The script runs on Ubuntu inside a bash shell's heredoc.

Thanks!

David J.