It allows your 3DS to locally verify and decrypt games without needing to connect to Nintendo’s servers for every single title.
Specifically, this file contains required for games released after March 2015. Without a complete or "full" seed database, many newer titles—such as Ever Oasis or Azure Striker Gunvolt 2 —will fail to install, boot, or display properly on modified consoles or emulators like Citra . What is the seeddb.bin ? 3ds seeddbbin full
On CFW, this behavior can be blocked or redirected. It allows your 3DS to locally verify and