What is the difference between a graded and ungraded Batman Knightfall comic and which is generally more valuable?

A graded comic has been professionally assessed and encapsulated in a protective holder by a company like CGC or PGX, assigning a grade based on its condition. Ungraded comics lack this professional assessment and are more susceptible to damage. Graded comics, especially those with high grades, are typically more valuable because grading provides authentication and a standardized condition assessment, increasing buyer confidence.