To achieve speed and scalability for real, industrial-sized contact, contract, and other large-data management. Quarter million, one million, etc. contacts, contracts, case histories, research documents, etc.
Some permanently-cached, auto-updated, locally-stored, portable, perhaps firebird sql, sqlite, so on?
Nothing unusual, nothing untoward, nothing unreasonable, just a built-in facility that will add lightning-quick search to large data set vaults, just like other apps out there (contact management, email, etc) have with integration of this functionality.