IndexedDB is a dumpster fire we all got screwed over with by Mozilla after they declared "inelegant developer aesthetics" of WebSQL and killed real life usable SQL engine https://hacks.mozilla.org/2010/06/beyond-html5-database-apis... This is how we ended with a cow shit IndexedDB nobody uses without some middle layers. This is one of those middle layers making using SQL database client side actually viable, by hiding IndexedDB as deep as possible.
I love absurd ideas like this because they sort of push the notion of what is possible. Some of my favorite projects have started out with "Crazy ideas but..."
That's actually not that absurd. It provides a familiar way to deal with data in scenarios where using IndexedDB alone would be difficult at the very least.