I use Local Storage for storing JWT Auth Tokens and other small stuff such as program options, But have never considered using it for storing a database. The thought simply never occurred to me.
I see it different, because I as a user use my Desktop at work to shop, and my phone at home to purchase or vice versus.
I would not want to write a program in which the data was not available on both my devices.
But for you, what your doing is experimental as well and you seem to share the same idea with the JScene developer.
You would have to do a proof of concept in code and try them and see which works better. Just fill your concept with fake data but make sure you can store and retrieve.
Not everything you can imagine has already been written and available as open source with support. Most web developers have never even heard of Local Storage, so the pool of choices for this will be very small. Your idea is an extreme concept.
Just my Opinion
If it ain't broke don't fix it
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