Because it’s not just desktop search in the conventional sense, it parses and indexes EVERYTHING that is shown on screen regardless of app.
Normal desktop search is fine for ‘where is file X?’ or ‘which document contains Y?’ but the point of Recall is to be able to deal with far more wide reaching queries, like ‘what website did I order a cake from last week?’ or ‘where did I see a great idea for a pizza recently?’, where it can find sources for natural-language queries across anything that was shown onscreen, whether it was a website, an email, a slack message, or something within any other app.
If anything I’d say Heaven’s Vault is the better of the two!
Sure, it’s way less polished and can be janky, but the language and the translation mechanics are so much deeper and more well-developed than anything in Chants of Sennaar.
The languages in Chants are tightly defined and very specific to what the game needed, so they’re not really usable outside of that context. But the language in HV is rich and complex, and you can actually learn to write new things in it.