This is fantastic. I have hemmed and hawed in doing similar things to build a serverless database. (both in the embedded sense and the FaaS sense) I could have a file or more per client and pay nothing until they load the app. There are a lot of use-cases as in mine that have low read frequency and low or no updates yet high write throughput. I would love to not have to pay for keeping all my indexes in hot ram If at all possible by sacrificing a cold-start and maybe some latency. I could see doing that with Litestream.
Another aspect of this db file per client configuration that is fantastic is the ability to offer data ownership and portability by allowing users to download the database file for themselves. No sql dump or service needed just a signed download url.
