The Seventh Amendment is important because it protects us from having our rights abused by the government. It ensures that the government cannot simply "railroad" us into prison on flimsy charges. By doing so, it protects us from government tyranny.
If we did not have the right to trial by jury, we could simply be tried before judges. Judges are, of course, government officials. They might (if the government wanted to be tyrannical) simply find us guilty of whatever the prosecutors said we had done. If this were the case, we would have no protection against the government.
By instituting the right to trial by jury, the 7th Amendment protects us from this danger. It allows us to be tried by a jury of our peers who will, presumably, ensure that the government actually has a real case against us and will not allow us to be imprisoned or otherwise punished without good cause.