[exim] Filters: "finish" and "seen finish" in "if ... elif .…

I have a working ~/.forward file that (simplified) looks like this
(the X-Spam-Score header is added by my hosting provider):



# Exim filter

# (1) put SVN & some routine work messages in the svn folder
if
$h_subject: matches "^SVN \\\\S+ commit: .* r.* - "
then
save $home/Maildir/.svn/


# (2A) put "hard" spam in spam1
elif
$h_X-Spam-Score: contains "++++++"
then
save $home/Maildir/.spam1/

# (2B) put spam score >= 3 in the spam folder
elif
$h_X-Spam-Score: contains "+++"
then
save $home/Maildir/.spam/


# (3) put everything else in the inbox
else
save $home/Maildir/

endif



In the examples in the Exim filter spec and wiki, I sometimes see the
line "finish" at the end of intermediate "then" clauses. What does
that gain?

I've been examing the contents of the "spam1" folder for a while and
am ready to start silently deleting based on that score. Do I just
change "save ..." to "seen finish" in clause (2A) above?

Thanks,
Adam