Pgbench : vacuum default behaviour history

Hi,

We're wondering why pgbench behaves this way by default:
"With neither -n nor -v,
pgbench will vacuum the pgbench_tellers and pgbench_branches tables, and
will truncate pgbench_history."

Why pgbench_accounts not vacuumed by default?

I've dug the history of pgbench until 1999. The vaccum of
tellers|branches was added when creating the pgbench contrib in Jan
2000, but I've not found any explanation or discussion.

My hypothesis is that vaccuuming the accounts was too long in 1999, so
it could be skipped for quick tests. And it was never changed.

Did I miss something?

-- 
Christophe Courtois
Consultant Dalibo
https://dalibo.com/