Illegitimate use (downloading a full BLES game without owning the disc) is software piracy and violates copyright laws.

: Add-on content (DLC) and save files are typically region-locked. A BLES game requires BLES-specific DLC; attempting to use BLUS content will generally result in the game not recognizing the data. Language Options

Is Downloading Retro Video Game ROMs Ever Legal? - How-To Geek

BLES identifiers are more than just labels—they represent regional licensing, language support, and game-specific patches. If you own a physical BLES game, creating a digital backup is a convenient and legal way to preserve your purchase.

guiding legitimate owners on how to manage their digital backups and use them on compatible hardware.