Companies can buy licences if they're uncomfortable with the Public Domain dedication:
[quote]
Licenses are available to satisfy the following needs:
* You want indemnity against claims of copyright infringement.
* You are using SQLite in a jurisdiction that does not recognize the public domain.
* You are using SQLite in a jurisdiction that does not recognize the right of authors to dedicate their work to the public domain.
* You want to hold a tangible legal document as evidence that you have the legal right to use and distribute SQLite.
* Your legal department tells you that you have to purchase a license.