“Simple operations against the database take ~10ms (and I’m being charitable!), while it’s common for me to be profiling SQLite at ~.01ms.”
IndexedDB is the only database every browser ships, and Chrome’s version is the slowest. So someone ran SQLite on top of IndexedDB and made it ten times faster than IndexedDB itself. The browser vendors had SQL in the browser once with WebSQL and killed it. A single developer had to sneak it back in through the storage layer they left behind.