Database management systems provide multiple types of indexes to improve performance and data integrity across diverse applications.
If many users attempt to insert at the same time, they all must write to that block and have to get in line, slowing down the application.
This is particularly a problem in clustered databases, which may require the block to be copied from one computer's memory to another's to allow the next user to perform their insert.
Reversing the key spreads similar new values across the entire index instead of concentrating them in any one leaf block.
Rot not only wastes space, but slows query speeds, because a smaller fraction of a rotten index's blocks fit in memory at any one time.