"Might vs. Magic"

Why use a Swiss-system tournament when there are only a few participants – a round-robin format would be better. Each player gets 8 games.

The thing is, I initially planned for up to 16 players – in that case, a round-robin format would be used, and if there were 16 or more, a Swiss-system tournament would be used.
Otherwise, we risk not finishing before the New Year.
And now, exactly 16 players have signed up, so I have some doubts...