Litestack provides numerous benefits, but the largest is live replication to S3-compatible storage, which SQLite will not do by default.
What they meant was https://github.com/oldmoe/litestack which has a lot of things built on top of sqlite, like job queue and caches. Rails 8 now comes with most of them out of the box.
My SaaS ran on litestack until rails 8 came out, then I switched without problems.