Piracy: Primary use is playing downloaded ROMs without purchase—copyright infringement.
Risks: Malware-laden kernels, bricked consoles, banned from Nintendo Wi-Fi (WFC dead, but local wireless affected).
Legitimate Alternatives
Original Cartridges: eBay, LukieGames, DKOldies, local retro stores.
Nintendo Switch Online + Expansion Pack: Includes curated NDS library (legal emulation).
Homebrew Only: If you only want homebrew (DSi/3DS via TWiLight Menu++, nds-bootstrap), you can run .nds homebrew from SD card without a flashcart on a modded DSi/3DS.