Purgatory? Please answer this Catholics?

Why would Jesus need to die for your sins if there was a Purgatory? If you believe in Purgatory, then why did Jesus come and die for us? To me it is a snub to Him, by this thought of Purgatory, it's telling Him "Thanks Jesus but no thanks, we have a better way to reach eternal life and that is Purgatory". It simply is not biblical and if you snub the Bible as so many Catholics do, you are snubbing God's Truth!