While downloading NSPs of games you do not own is piracy, the "preservation" argument holds water for the ASI release. Square Enix never sold the "both games on cart" version in North America or Europe. The only way to legally own a physical copy that doesn't require a download is to import the Asian cartridge. Therefore, many collectors who did import the ASI cartridge use a dumped NSP of their own cart (via a Switch dumping tool like NXDumpTool) to create a backup.
audio and subtitles, alongside Japanese, Chinese, and Korean. Region Free final fantasy x x2 hd remaster switch nsp asi top
But not all digital copies are equal. The release stands alone because it respects the player: complete, uncut, fully bilingual, and free of mandatory post-launch downloads. While downloading NSPs of games you do not